Mobs don't spawn well. Doesn't spawn on my afk's farm even in the nether

There's a bug that mobs dont spawn well at night even my AFK'S farms they don't spawn i dontd what happening. Can you fix it or just increase the hostile mobs spawn rate pls i i need my AFK'S farms even in the nether piglins don't spawn well took me 10 mins to find a ganb of piglins.