Welcome to TAW!
As far as the Filioque, I don't know if this will help but it made sense to me when I saw it after I already understood well enough to see the problem.
One thing is that, while all the Persons of the Trinity are God, we believe that the Father is the source. The Son is begotten of the Father. The Holy Spirit proceeds from the Father.
Here's an illustration
But if you have the Holy Spirit proceeding from the Father and the Son, it implies something like this
(Btw, the site those images came from is not helpful. It's just the closest I could find to what I saw before.
The first thing I usually think of in terms of whether or not Peter was infallible and/or had ultimate authority is - what about the council of Jerusalem in Acts? Peter did not prevail, James did.
And one of the most stark illustrations of development/changing of doctrine involves the Assumption of Mary. How is it that the Church has the Dormition of the Theotokos as a major feast, marked for centuries, and now the Catholic teaching is that she never really died?
There is more. I have such respect for my Catholic brothers and sisters that I do not like to point such things out for sport, but if you are seeking, it seems worth mentioning.
One thing I would say - give yourself time to look deeply into the differences between Catholicism and Orthodoxy, and don't rush into confirmation. If you become Catholic quickly and then decide to leave, well, I have seen a tremendous amount of pain and sometimes fear involved with abandoning the Pope.
To me, it is very subtle, and I'm not the best person to explain it, but really the view of God, grace, punishment, etc. is different between the Catholic and Orthodox, and that has been one of the main things that really opened my heart to God.
Again, welcome to TAW!