For reference here’s probably the best comparisons I’ve seen between 2011 1080p releases and the 2019 4K releases.
TPM: https://www.hdnumerique.com/dossiers/819-test-4k-ultra-hd-blu-ray-star-wars-I.html
AOTC: https://www.hdnumerique.com/dossiers/820-test-4k-ultra-hd-blu-ray-star-wars-II.html
ROTS: https://www.hdnumerique.com/dossiers/821-test-4k-ultra-hd-blu-ray-star-wars-III.html
Pretty minor improvements, but still worth it. It will be good to see what AI enhancements can do to the footage.