We could go with the same formation and personnel we played vs Villa: Walker, Dias and Laporte as a back three with Rodri and Bernardo in front. That means when we lose possession either Bernardo covers LB or Laporte does and Rodri drops back in to the defence. It worked yesterday but it might be asking a bit too much from the players to do it against a much better team who will have far more of the ball than Villa did. It would also be harsh to leave Ake out given how consistent he's been this season.
I think it's more likely that we'll play Walker and Ake at full-back to deal with Martinelli and Saka. The only problem with that is if Walker is asked to step in to midfield because that was a disaster against Newcastle earlier in the season when Saint-Maximin gave him a torrid time. We could play a traditional 4-2-3-1 with Bernardo staying close to Rodri which would give us more defensive solidity and wouldn't leave us short in midfield. The only downside is it would leave KDB more isolated and it'll be easier for Arsenal to mark him out of the game.
Can't wait for this, should be a fascinating encounter and if we win we surely become favourites for the title.