Vivaldi is pretty pro-privacy. Every time Chromium adds a new API with privacy implications, Vivaldi makes a blog post publicly committing to disable or remove it from the version they ship. E.g. the most recent update, the headline feature is disabling the Idle API by default: https://vivaldi.com/blog/vivaldi-gets-more-private-delivers-...

They also had a pretty long post about why FLOC is bad, and I believe have committed to retaining Manifest v2 for extensions.

Other prominent privacy or privacy-adjacent features include a built-in ad-blocker and heavy investment into on-device translation features.

I'm not sure how much work they put into preventing fingerprinting techniques. I don't get the sense it's a high priority.