Okay ill bite.
The Hashrate coming off ETH is so enormous that only 10% of the ETH hashrate is enough to make every other POW coin unprofitable.
ETH classic will absorb the ASICS so GPUs will never be profitable there, rest of the coins will be swamped by the remaining.
Even if you use have the most efficient GPU in the retail market that still doesn't compare to the larger mining operations who have access to more efficient GPUs that were never released to the public.
Quote from HUT 8 mining VP
Then of course comes the power question, Well here's a
quote from Hive Block Chain on their plans post merge.
So the tiny bit of profits that will come from other POW coins will go directly to the large miners who not only pay extremely low power costs compared to retail, they also have to most efficient hardware.
The simple fact is that the ETH network hosts the majority of DeFI and generated the most revenue for miners, post merge some miners will try the whattomine bingo but I doubt that's going to be worth the trouble.
TLDR : Buying a RX 6600 hoping to mine after the merge doesn't seem like a good idea.