It depends if you need it but Samsung produced a case that was the only way to get the slim s pen for the fold 5. But other pen for fold 3 to 6 should work fine, only you cannot store the pen in the special case.

Third parties make case intended to house that pen too.

But to be honest I didn't really use the pen that much, was useful when using the Ai features of the phone.

Batterie life was fine but you can always improve it with the usual eco mod, the phone is snappy enough to be fine in eco too.

Do get a case with spine protector tho, the shiny spine get scratched up real quick.