even with literally using the threat of death forcing the character to work with the party, there is ALWAYS that one dipshit who wants to bitch and moan about how I’m “railroading them/preventing them from roleplaying their character” by doing so
This is an out of character problem that should be addressed by talking to your players at session 0 (and at any other time it arises). The manner in which you create characters is irrelevant here because it's an interpersonal issue, not a mechanical or narrative one.
either you have been incredibly lucky with groups or have let Critical Roll give you rosey glasses about the role-play capabilities of the average player
I don't watch actual plays. Never have. Tried Critical Role for a few episodes and didn't see the appeal. I don't think it takes an awful lot of roleplay skill to accomplish. Because I've seen it work many times with very ordinary players. Ordinary, but participating in good faith, which is the bare minimum. If you don't have good faith, you shouldn't be playing.
But it's pretty clear from a lot of your tone and actions here that you are not participating in this conversation in good faith. Unless that changes, I'm out.