I agree with the 6/8 but not because it allows Rice to play as an 8, but because our backup 6 (Jorginho) needs to be always paired with someone more defensive in midfield. A new 6/8 can play with Jorginho or ESR/Vieira/Havertz depending on the opposition.

Also, w.r.t. Rice, that we were in for Mount should be proof enough that he was always meant to be a 6 (if not consistently this season, then long term), and he would play as the 8 next to Partey in the tougher games. Again, I am not claiming Rice as an 8 was always out of the equation, but the fact that he has played as a 6 through most of the season should be enough. Even when Partey went off injured, and we had Zinchenko back to invert, Arteta didn’t immediately move Rice to 8 but kept playing him as a 6, even against United and Spurs (in this match with Vieira and Odegaard in front of him). It was only against City, Chelsea, and Sevilla away that you could claim Arteta played Rice as an 8 for tactical reasons.