For how long are you willing to mine Ethereum? because very soon your mining rigs won't be able to mine Ethereum because of the upcoming upgrade called ETH 2.0, the only way to get Ethereum will be through Proof Of Staking algorithm
hmm do you have source of this? I have seen that proof of stake wont be there for years and mining eth will be ok. The most important what i researched is i need alt east 6gb graphic cards, because of the DAG file, and 4gb wont be valid anymore in 24th December 2020