He is using VPN because so he can get bigger claims from some faucets.

That's why I give ALL user thesame amount, no matter what country they are from.
I believe in equality.

Me too believe in equality but google adsense don't Angry

You can give small reward for shorter time with adjusted reward according to your revenue.

There must be some adnetworks which pay for russia and ukraine any guess?

I think nothing is better then AdSense .
even for Indian traffic AdSense pays 0.1 - 0.16
so blocking particular traffic is not good idea .

Ofc its not a good idea but small investors want fast return so they try to catch all high return countries.