I don't understand the "burned by OGS" bit and this is not just specific reaction to your post, because I see this posted often.
OGS had couple of very decent seasons (finishing 3rd, then 2nd) and a 3rd season where things went off the rails and he rightly got sacked. He has been better than a couple of post Fergie managers (Moyes and Amorim) and not too different from how we did under Ten Hag and LVG. They all had couple of decent seasons, maybe a minor trophy, not really challenging for the title, then they get sacked after that. His biggest failure was playing for penalties on the EL final against Villareal, if he had won that his reign would have been as good as Mourinho's reign, which was the best in the post Fergie era. But without any of the exhausting hysterics and dram of the special one.
At some point we have to accept that he did OK and the problem was largely bad recruitment and leadership from the board, while also acknowledging that he was obviously not of the calibre of Pep or Klopp which were pretty exceptional managers. I think for being just a "good vibes" or "caretaker" manager without any serious pedigree and for operating under the ignoramous Woodward and the Glazers, he even exceeded expectations. We even played some good football during his reign. It was no disaster by any means. I wouldn't say he is a cautionary tale, Amorim is much more of a cautionary tale. The man nearly put us in a relegation battle and broke historic negative records.