As long as you are able to purchase GPU at the correct price, then you are safe.
Avoid Polaris, Vega can be very good for Ergo, not for eth
1660 super,2060 super,3060ti and 3070 are the one offering the best Mhs/watt ratio.
Ergo,RVN,may be ETC will go up at least for few month compared to the rest of crypto, while some miner will move away from ETH. Long term is in function of the project, but I can't help with that.
To be fair, as gas prices of eth will be high regardless of cutting the miner part, after a while when some people will try to go for makis a POS node, I don't see eth in good shape
I concur with this proposal"You can buy a mining farm on used Px 470 4GB video cards. The payback period for these mining farms is 6-8 months. After Ethereum changes the algorithm, you can buy more modern graphics cards for good from miners who want to go out of business. Your costs are practically zero" as its exactly what I have done initially