I don't know how Google Photos stores the photos. Unless you have a backup, it is hard to see if this is a change at the level of files, or that Google Photos has a unique way of storing them that introduces changes to HDR-enabled files. As I said, I'm quoting what worked for people who faced this issue before.

I only use Google Photos as a photo viewer, completely offline, no cloud backups. Like I said, there are definitely file level changes which I inspected on a copy of the files on my computer. Anyway, thanks for participating. I hope I didn't come off as rude.