I don't think there'll be any such optional systems in 1.0, they'll present ability scores in preset arrays with 'class' ASI's, and that'll be that. You can fiddle a bit but really, there's so much else to play around with and you want to start playing. Doubt they'll allow rolling either, that's just a time sink - 'just one more reroll...'
Going by TT convention, every DM has a preferred system and players create according to that. BG3 is such a DM. This idea that there is one true way doesn't match my experiences. Tasha's and 1D&D, like BG3, are just latest iterations.
Guess it pays not to get too invested one way or the other in ability score generation method, including BG3's, it'll likely change whatever D&D game you play next.
