Getting fewer coins lately from payouts?

I’m getting fewer coins on my RVN payouts lately and I’m not sure why. I’ve even tweaked my OC settings and added another 3060ti… and I’m getting fewer coins than I was three weeks ago. Can someone ELI5 why that’s happening? T-Rex on ethermine. About 200mh. 3x 3080 LHR, 1x 3060 LHR, 1x 3060ti LHR