Agree, except I feel that Gray has earned the right to play in this one...our most important match so far this season. After being outstanding out of position, in three different positions this season. If Bentancur and Biss had been brilliant lately, then yeah sure, go with the experienced guys. They've far from it though, so I'd give Gray the nod and keep one of the two in reserve to close it out (if we, knock on wood, get there).
He deserves it, I agree. But I think it's more likely we'll see him come in as a sub where needed, with Sarr providing running power off the bench in the midfield. Gray is not ready to start in midfield in a game like this, and Davies is solid at LCB, with decent positioning and experience to help Spence deal with Salah.
I can't see Gray at LCB with Spence at LB for this one, unless Danso slots in at LCB and Gray on the right, with Davies benched.