I think it's best to read what deep thinkers have said and make up your own mind - or keep an open mind if you feel the arguments are not decisive. Hume was the seminal contributor to this field of thought, so his arguments are worth serious consideration.
I never heard of anyone who said you cant go from is to ought a) giving their life savings away b) sawing their legs off c) stuff like that.
It seems whatever their mouths say, in general people do have a way of going from is to ought.
You tell me - as I understand it, that's how moral positions are usually justified.
My point is with Hume, if you say you ought to believe him then he is wrong - as you've gone from reading his Treatise (an 'is'), to a conclusion you believe you 'ought' to hold.
So believing you ought to believe him undermines that belief. It seems like its an absurd thesis, of the kind: "I ought to believe oughts are underivable"...
No, I'm not saying that. I'm saying that "... (good) health being good for the person whose health it is" is tautological.
But why are the terms "good" and "health" so commonly conjoined when a person is not sufferening from gross illness. Is it a random coincidence we make an ontological state (health) something approved of (i.e. we call it good) or preferred?
What is 'better' is the question. But sure - we inevitably derive ought from is because we only have our predispositions and a lifetime of experience of what is (or at least what appears to be) from which to derive them.
The question is whether it can be justified without begging the question. I have sympathy for anyone in intolerable pain. My view is that in some circumstances assisted dying is a Good Thing. Some people disagree to the point that
they would take a life to stop it... This is where ethics
ought to come in
IMO these scenarios and disagreements occur because culture is soooo complicated. If you re a Catholic than that will influence your position on these things. If youre an atheist another view is more likely. And that difference was partially down to some guy named Paul having a vision of Christ 2000 years ago etc.
That's what we like to tell ourselves - but that may just be the way the lizard brain makes us feel we're in control. If we didn't have a conscious sense of agency, we'd feel like helpless passengers...

"
We must believe in free will, we have no choice"
Isaac Bashevis Singer
I'm kind of "neuro-
Thomist" with regards to free will. When we act in accord with our nature or higher ideals, and do so with less social resistance, we feel free easy and self expressive. Probably this is accompanied by endorphins and oxytocin release.
If we are forced against our ideals, we then have resistance to our 'nature' and it seems likely (I'm no PhD student) release stress horemones like cortisol.
I look to the etymology of "free" ("priya" which means beloved) for inspiration in this.
Imagine in primitive society how the term 'free' may have been used. Its original causes. Free marriage, not rape. Free trade where one is not robbed etc. Free life rather than slavery.
I think this approach might be related to "
cognitive archaeology". The deeper history of our concepts.
Then, we can also look at the neurochemistry that is associated with these social facts. So freedom is not a 'a priori' state (ever there, or ever absent), its more of a contextual thing, with degrees of presence or absence in certain situations.
Only later did the metaphysical baggage of "Are we n the hands of the Gods....?" or "is it all predetermined, an atom cascade from the Big Bang?" etc. cloud the issue. But that's over 2000 years later than the onset of "freedom-talk", or even more.
I'm not sayin' its the only valid analysis, just
a way.