DigitalFoundry: Doom on Switch: The Complete Technical Analysis!

[JRPGfan]

"prolonged loss of fluidity"
actual gameplay slows down, like a slowmo effect, when performance drops.

shows a fight with like 4 enemies and fps running in the 19-23 range.

recammendation from DF:
Play "easy" campange, has less enemies, so you wont be playing as often at 20fps.