Try one card at a time directly on the motherboard, if it works add one and so on. Are all the mining optimal bios settings set? On the latest bios as well?
Did you Update Hive OS ? as you have the 0.6.213… I had the same problem with my 2 x RX 6700 XT hashrate that went down to 41 Mhs. I went back to : 0.6-212@220105 and everything is back to OK give it a try