If you’ve got cash to spare and the hardware to play it, I’d probably just suggest you get the latest 4K/UHD Bluray releases. It’s the best video quality officially available for all nine films, and it makes sure you’re as legally ‘in the clear’ as possible when downloading fan versions, which I would absolutely recommend you do to supplement that set.
For AOTC, Schorman’s HDTV preservation is arguably superior in quality to even the new 4K Bluray, due to not having the overzealous noise reduction that the 2011 and 2020 Blurays suffer from (overly smooth looking skin, lack of small details). TPM is also cursed with too much noise reduction, but unfortunately for that movie the HDTV preservation is even worse because it was sourced from an earlier, poor quality scan of the film, so you basically just have to come to terms with that.
For the OT, I would recommend you check out 4K77 and 4K83 (4K preservations of the original unspecial theatrical versions), and D+77 and D+80 (semi-despecialised edits of the movies based on the new 4K versions) which are worked on over at the Star Wars Trilogy Forums.
If you’re short on cash, the new 2020 4K/UHD Prequel Trilogy Blurays are only a tiny tiny improvement on the 1080p 2011 Blurays, so the old prequel Blurays would do just fine. I’d recommend strongly against the 2011 OT Blurays though as they’re much worse than the new 2020 Blurays, on account of being based on an older, inferior scan of the film prints, and having some seriously misguided colours. For the ST, you can grab either the 1080p or UHD Blurays really - there’s a bigger difference than there is with the prequels, since the ST was actually shot on film rather than on dodgy early digital cameras, but any Bluray you get of those movies will be fundamentally the same image just at a different resolution/colour depth.