For Return of the Jedi, Adywan might know which shots from the 2011 Blu-ray look better, since he already replaced some during the color grading of the 2020 BD. It could be worth asking him.

For Star Wars, as YAREL_RGP already mentioned, TGWNN would be the best person to ask, though I’m not sure if his 2020 BD remastering project is finished yet.

As for The Empire Strikes Back, I’m not aware of any similar project, but Adywan did mention at least one shot from the 2020 BD with bad framing. Maybe he knows of other problematic shots as well.

It would definitely be helpful if users could share their findings on specific shots with heavy DNR, frozen grain, or other issues. That way, projects like Despecialized (or any other restorations) could benefit from that information. A community-driven “worst offenders” list could make things much easier to tackle.