For me the most efficient card right now is the Rx 5700 xt with 55 Mhsh at 115 watt which is the best for the moment and it does not require a PSU larger than 1000 watt for 6 cards which gives you about 330 Mhsh of power.The RTX 3070 if found at less than 1800 EUR is another great option for efficiency speaking and not consuming a lot at 60-63 Mhsh for 160 watt.
The best for the moment in power is RTX 3090 with 120 Mhsh per card.
Ur in a dive bar, and a drunk say's "If u can have any woman tonight, who would it be", you reply, there is only one gal in this bar,same-same with GPU today, all there is for sale is used shit that has been mined to death sold on EBAY for 500x, please just admit that this OP is a joke right?
In two years the GPU card will be worthless, until then just stay away, many of us bought 5+ years ago, and just don't care about the current scammer scalpers running the meat-space.
Last summer I was buying rtx-3070 rigs at $250/card ( prices paid here in Asia ), now they're $2k card on amazon, whats a mother to do? Just keep mining and enjoy the show.