In the modern day, purchasing ANY game on release seems like more of a gamble than it's worth. So many botch releases, half-finished games and glorified early access "Full releases"...
It's the same idea about why pre-ordering has been dumb since the switch to digital distribution (At least back in the days of physical retail, pre-ordering meant you reserved a copy to ensure you got one before it sold out. With digital distribution there's lliterally infinite copies available)
Even for particularly well regarded games it's still often worth waiting a while for bugs to be patched out and any extra content to be added post-release (Something that Elden Ring did as well as BG3).
Larian specifically, have a history of making Definitive Editions for their games. So there might be a possibility for a DE of BG3 down the road, which would be the ideal time to pick the game up (Though it's not a guarantee that BG3 will have a DE) as the DE has typically been the game with the most polish and extra content.
As for "Early Access", it's one of those things that you need to consider before buying into. EA isn't just "Play the game early" but rather "Play the game mid-development" meaning that you should expect things to change over time and for the final release to be somewhat different.
I personally avoid EA titles because it's not for me. I don't like playing half finished products, nor do I like spending money to be a beta tester (I'll beta test for free, to help find bugs and give feedback on stuff, but paying money to do that? Nah fam).
