Question about mining with different cards and results

So i have 4 cards mining RVN. 2 are 5700xts on a separate rig and those are giving me 28 to 30 m/hs and i have a pc my gf uses with a rx 580 sapphire 8gb whichives me an average hashrate of 12 to 14 mhs while my pc with a non sapphire rx580 8gb gives me a similar hashrate to my gfs sapphire. But the hashrate on them all vary and im gettong about 40 rvn a day or 30 using 2miner for all 3 rigs. It seems a little low for me. My 5700xt rig keeps giving me a dead card error so ive been looking for a solution to thar which i cant find.

My rx 580 cards are limited because theyre connected to a monitor so apparently the program limits them.

Either way, any way to maximize my earnings?

Also, ive read mixed comments on people mining eth then trading it for rvn, or should i just mine rvn directly?

Hopefully this isnt confusing. I have 5 3070s mining eth including 2060 and 2 1660 supers. I have a 3060 coming in as well as a 6800. Hoping more can come in tje near future. I would not mind swapping all to RVN either. Im in it for the long run.