Fun fact: no non-trivial program is ever free of bugs.
Well, "trivial" is maybe the wrong word. You can prove programs, but thats not possible for really large programs.
In sufficiently large programs, it is estimated that they have a bug every 50 lines of code.
Some programs like TeX are famous for having been carefully finetuned for decades and being practically bug free, but thats the absolute exception.
Vim is another program I can think of that is at least extremely low on bugs; its an editor used for programming. Its complicated to learn but super powerful. I never heard any programmer losing their source code when using vim, though of course you also should use version control for backups (and coordination with other programmers etc).
So yes, Baldurs Gate 3 will always have bugs. Its the natural consequence of being at the cutting edge of how complex a program can be. That said obviously all known big bugs should be fixed. Fortunately Larian has said they will continue bugfixing, even if adding new big features to the game has finished with 8.x.