Will hopefully help the handheld performance/battery. I know I personally have been waiting for FSR 2 before really getting into BG3 on my deck.
As an odd side note, FSR 2’s addition to the game wasn’t mentioned in the patch notes. Also there’s a negative interaction between TAA and FSR 2, so you’ll have to set anti-aliasing to SMAA or disabled if you want to use FSR 2.
It does indeed help performance on the Deck. Though not much in Act 3, which is still heavily CPU bound and isn’t efficient at all in the way it handles multithreading. In fact, Baldur’s Gate 3 still suffers with treating modern CPUs as if they were Core 2 Quads.
FSR 2.2 also does still suffer with some heavy occlusion artifacts, but in the Deck I find them much more tolerable than on a monitor.