I seen the pic. Hard to tell how you have the water lines... but looks like in at the bottom port.

Edit: I know with the hydro copper they say it dont matter which side is in.. but might matter on the ek blocks.. I'm always using the connection closest to the i/o plate as in.

No idea of your rads but 60-70s C is like air cooling temps.

I get 31-33c max on load with my 2080ti kingpin on a hydro copper. 39c max on the default aio cooler prior.

Before tthat with my 2080ti ftw3 with hydro copper I'm thinking 36-39c?

Kingpin at 33c max load with 2x 480,2x 360 and 1 540 rad.

Room temp max 72f. Water temp like 22c max.

Solved the issue. It was a bad GPU.  But the motherboard and each card worked fine solo. It was not till I replaced the motherboard that it was clear the new motherboard hated one of the GPUs as it would freeze and crash in Bios. After a quick RMA the new card and cards run great in SLI and solo. Thanks for the help and support.