I sometimes play the Grob in blitz, where most of my opponents attack my g4-pawn with 1...d5. However, some opponents play 1...e5, leaving me in a weird position. Is there any way to play against 1...e5, while also leaving chances for many tactics along the a8-h1 diagonal?
You played 1. g4 and you're not pleased with a "weird position".
Do you know why 1. g4 has any value other than comic? You're aiming to post a knight on e4, and the g4-pawn is there to knock down ...f5.
I mean, if they're playing ...e5 and not ...d5 to give you the typical c4 counterplay, you ought to be happy with that because they're not contesting the square you want for your middlegame outpost.