I have always maintained that the apostasy started even before the apostles died.
Quite frankly, this is your problem, not Christianity's.
Our Lord, God, and Savior Jesus Christ is a victorious deliverer, having nothing to do with Mormonism's incompetent buffoon of a Christ figure who cannot even choose his own apostles properly, nor protect his church. If it weren't for the fact that you stole the name and title (and can sadly rely on the reality that most Christians don't participate in theological discussion like we do here, so they have no reason to assume Mormonism isn't Christian when it says it is), there'd be no reason to ever consider them the same.
By 95, and all but 1 apostle was living, the scriptures tell us that there were men that were rewriting the rule
The Didache does not rewrite any rule -- it establishes it, as regards baptism. That's the entire point of the text. It is the teachings of the apostles given to the nations.
We know from this scripture that men were openly defying the apostle John:
3 John 9 King James Version (KJV)
9 I wrote unto the church: but Diotrephes, who loveth to have the preeminence among them, receiveth us not.
Does the existence of this one guy who is called out by name do anything to alter the requirements for bishops and deacons, or change how baptism is to be performed? (The actual things that the Didache covers)
No. It doesn't. It is entirely irrelevant. Furthermore, if one guy acting like a puffed-up jerk is enough to invalidate Christianity forever, then Mormonism has invalidated itself since day one...or whatever day it was within the founding of his religion that JS was caught with his servant girl in the barn and tried to subsequently play it off as part of some revelation or other. But note that we don't operate as you do, so I'm not making that claim (only showing how silly it is for Mormons of all people to make it).
So would it be surprising to you that Diotrephes would set aside the apostles and without authority, choose his own bishop, maybe himself, and encourage all other would be bishops in nearby cities to do the same, so he could start building his empire of bishops and cities.
Not at all, because I know Christian history and this is what people do. That's also how I know it doesn't prove some sort of worldwide, irrecoverable apostasy that needs JS' or anyone else's help to fix.
We know by the epistles of Clement of Rome that the Corinthians were throwing their apostle-appointed bishop out, and putting in their own popular bishop.
Here's an idea, if you're ever done perverting Christian history for your purposes long enough to consider it: the fact that HH St. Clement wrote to the Corinthians about this showed that he recognized that it was a problem, and the fact that he recognized that it was a problem (which it was, though it should be pointed out that a schism within a particular church does not a worldwide apostasy make) showed that there were still some bishops who were righteous and following the true path of Christ and His apostles, so there couldn't have been a worldwide apostasy. The Church at Rome was fine, as was the Church at Alexandria, at Antioch, at Jerusalem, and so on. HH's letter works against your point just as much as it does for it, unless you for some reason want to paint the saint as being part of the schism that he was clearly not a part of (since this was long, loooong before the Roman ecclesiology would develop to where it is today, where RCs would say that their Pope has the right to interfere in the workings of another local church so as to force them to follow his command).
So these new rules were happening even earlier than 95.
It's not some kind of 'new rule' to write to another church to tell them to get their act together. It has happened throughout history, and always will. Whether it's the Eastern Orthodox telling each other to get their stuff together regarding Ukraine, the Oriental Orthodox looking askance at the situation between the two Orthodox churches of India (which are both in communion with us, but sadly not with each other since the 1970s), the Roman Catholics dealing with several sedevacantist groups, etc. Even the Nestorians, who have been out of communion with everybody else since the aftermath of the Council of Ephesus in 431, have their own schism with the 'Ancient Church of the East' people, who split over some reforms in 1964.
And
the same spirit of dissent exists in Mormonism too, although you'd probably like to pretend it doesn't. So why is this evidence of the unraveling of Christianity before 95 AD, while the same thing is not evidence that Mormonism is corrupt?
Just think what happened by 120 when the apostles were all gone.
The bishops they had already ordained decades earlier either continued in their calling or had ordained bishops to follow them who were by then continuing in the same calling. Oh the horror!
Whoever wrote the Didache I believe also said it was OK to sprinkle members if there was not enough water to fully baptize them.
Which it is. This is commonly done in places like Ethiopia, where water is at a premium since the country still mostly survives on agriculture and inconsistent rains have led to semi-regular famine, particularly in the highlands (where the majority of the population is Christian). All the babies and adults received that way are fully baptized, recognized by all the churches of Oriental Orthodoxy (well, for those who are received into the traditional church of that country, which is the majority of the country's Christians; there are also Roman Catholics and Protestants), even as the standard communion-wide is to receive new Christians by triple immersion.
So not only the rules for ordination were changing, but the doctrines of the church were changing too, even before the death of all the apostles.
Again, no they weren't. You're just flat-out wrong about this, Peter.
Do you deny that the first bishops of the church were ordained by the living apostles?
What? Where is this coming from? Why would I ever deny that? My own Church was founded on the preaching of the apostle of God St. Mark, so of course I do not deny that. That doesn't mean I buy into Mormonism's phony baloney idea of 'apostle' being some kind of inheritable office, which I don't. Not for even one second.
And where in the scriptures do you find the Didache rule of "Therefore appoint for yourselves bishops and deacons worthy of the Lord"?
Oh don't get all sola scriptura on me when convenient. We both know that this is not the rule in Mormonism, because if it was you literally couldn't be Mormon. That's how much your religion violates the Holy Bible, which we Christians wrote, canonized, preached, and continue to preach, even as your religion calls us false professors of abominable creeds and all manner of similar absolute lunacy.
Get out of here with that.
I believe the Didache is not part of the canon for a reason.
What? Nobody ever said it was part of the canon. It has never been part of the canon.
The Didache does demonstrate that the church was already changing the rules and changing the doctrine very early on. It demonstrates that the church is starting into the apostasy.
I guess it does if you already believe that that happened, but for the rest of us it very much does not. The disinterested person would read it as the earliest example we have of a Church orders text, which is exactly what it is. Your commitment to Mormonism's blatantly false alternate history narrative is causing you to read it in a way that is at variance with literally everyone else on the face of the planet. Again, this is your problem due to your fidelity to Mormonism, not Christianity's problem.