Ulreich only played because Neuer was injured. They had gotten that far with him, can’t say it’s strictly down to him, even though it was a howler the pass back did him no favors.
While I ultimately agree with your overall point, as defenders feel more secure with a DDG back there than say Mignolet, can you name a keeper that would be in Arsenal’s tax bracket that would be an upgrade on Cech? He’s a solid enough keeper, which would be difficult to upgrade on given their hesitance to spend. Oblak would cost 60 million easily in today’s market, and Arsenal were hesitant to pay that for PEA, a forward. Trapp has been up and down, Donna same as Oblak, and tbh I struggle finding other candidates off the top of my head, although maybe Lopes from Lyon, but don’t know how he’s been this season. The fix is not so simple for that.
I knew about Ulreich being back up, just wanted to highlight the goalkeepers being a massive factor in who went to the final.
I fear like I can't give you many names because you have to watch multiple full matches from smaller teams to rate goalkeepers and can't do them proper justice with just some highlights. However, I believe you can get great keepers with good scouting. Werder Bremen got Jiri Pavlenka from Prague for €3m and he is now the best Bundesliga keeper (except for Neuer).
Some suggestions without much scouting effort:
Rui Patricio - very reliable keeper for years, now rumoured to go to Napoli for €15m
Bernd Leno - has a release clause of €20m, good shot stopper, mediocre in the air but great at saving penalties, which is a big plus at Arsenal
Samir Handanovic - one of the best keepers in Serie A, not avaible now because he extended his contract in december. Would have been possibly available if Arsenal pushed hard for him because Inter was out of the CL the last few seasons and would have been cheaper than Oblak for sure
Mattia Perin - I won't bother pretending I have watched Genoa in any capacity. Anyways, everyone I talk to about Serie A says he has been one of the best keepers there in the last few years and he would have been the Donnaruma replacement at Milan if the latter one had left last summer, that is confirmed by his agent.
Lopes has been good this season apparently. Please keep in mind I only came to that conclusion by watching highlights of every Lyon game this season but no full match.
Oblak is indeed too expensive. Atletico said any buyer would have to pay the release clause, which is €100m, and I have a hard time believing the repeated chatter of Liverpool preparing to sign him. Only possible for Man Utd in case they lose De Gea or Chelsea if they get good money for Courtois.