We are unlikely to get past 2 beams in BG3 since I think it will cut off at 10th level.
They've gone back and reconsidered the level cap and as a result we'll be able to go a bit beyond level 10.
I don't think we know how far we'll be able to get, but considering Eldritch Blast gets its third beam at level 11 I'd say there's a very good chance of us going past 2 beams in the full release.
