You're really pushing the limits of those 5700 xts.  I have 6 5700 xt red devils running:

1350 gpu/850 volts/885 memory, and the memory timings from 1500 MHz.  I'm getting about 54.7 mh/s.  Fans run ~24% with temps in the low to mid 50s for the gpu (I'm on ubuntu so I'm not sure of the memory temp).  They are rock solid.  That is slower than your top, but about the same considering your throttling. 

It's up to you, but your only option is to scale back your memory or open them up and put in better thermal pads.  (I'd suspect your cards would last longer too.)

It's all about winning or losing the silicon lottery. It's hard to treat them all the same.