Old Vivaldi user here. Vivaldi is quite lacking in privacy, and chromium made it worse to use over the years. I would not recomend it.
You would be better off with Librewolf, if you want a more fancy fork you can try Floorp (silly name I know), it’s quite similar to Vivaldi regarding customisation and options.
Or you could try Zen…but as far as I am aware it’s still in alpha, lack some options, especially regarding privacy so may be not the best (you can still edit the about:config though). I keep trying it again and again, only to be disapointed because it’s still too fresh.
One similar thing happened to me on windows 8 (except I wasn’t testing it, I lost everything on my pc that day because it didn’t just fail to update and restore…it just fucked my drive with it !), so it’s not even a new type of issue. Even windows 10 was fucked, had a friend who never used bitlocker, never even knew it was a thing, who got his pc encrypted by it after an update, unable to unlock the damn thing, every solutions failed and had no other choice but to wipe his drive. It’s crazy how bad and unpractical windows can be.