That the animation that plays after you fire the weapon is not fast enough to allow the player to switch and fire to another weapon.
I understand that setting the weapons with A_Ready too soon will also be an issue while refiring, but I think that if you add "Hold" states with a few tics of delay it could prevent too fast firing and too slow switching at the same time
They are not quickswitching as they need to, compare it to Doom Eternal's quickswitching and you will notice that the switching after fire is pretty much instantaneous.
I think that the fire animation is too slow
What do you mean with too slow?
That the animation that plays after you fire the weapon is not fast enough to allow the player to switch and fire to another weapon.
I understand that setting the weapons with A_Ready too soon will also be an issue while refiring, but I think that if you add "Hold" states with a few tics of delay it could prevent too fast firing and too slow switching at the same time
That is intentional. These weapons are meant for quickswitching.
They are not quickswitching as they need to, compare it to Doom Eternal's quickswitching and you will notice that the switching after fire is pretty much instantaneous.
That's what's missing in this mod.