No problem, I don't love having 2 fairly expensive 'keepers in the squad should you sell Dubrvaka in 34 and BB in 37 but I'd really want to avoid using Dubravka in a bench boost away at Arsenal, and a fair number of the fixtures for your players in 38 don't look great to be using the BB chip on that week anyway as already stated. You can afford two relatively pricey goalies too with the 3.8m in the bank.
So someone who will play in 34 and has a solid 37 if using BB that week. Perhaps as a bonus someone with a better 36 than Sanchez too as he is away at Liverpool then. A bit early to look into it all, early thoughts anyway:
I would have said Lammens as he seems to have decent fixtures in those 3 weeks (34, 36 & 37) but you already have 3 players from United. He's got Brentford home, Sunderland away, Forest home those weeks. 34 and 37 good, 36 probably better than Sanchez at Anfield.
Leno not bad. Villa home in 34, Wolves away in 37. 36 is Bournemouth at home, arguably better than Sanchez that week.
Pickford? Plays in 34 now that Leeds have won against West Ham in the cup. West Ham away in 34, Palace away in 36, Sunderland home in 37. Two away but I think Everton have been better away from home anyway. Expensive though.
Could do something a bit crazy and bring in Raya for Dubravka, you can afford it. Plays in 34 at home to Newcastle, Arsenal the best defence in the league, probably use him every week including in 36 away at West Ham while Sanchez is at Liverpool, BB with him at home to Burnley in 37 and Sanchez at home to Spurs. Highly unorthadox move considering the price of the 2 goalies you'd have but it could be a case of why not by then.
Maybe some other options will look good by then too. See what emerges by the time 34 comes around.