Just tried it and wanted to share my first impressions with this forum.
I like tab groups and while it is good that you can disable the background color tinting for the window my biggest gripe is that “streamlined” widget combining tabs and address bar. You can never predict where address bar will be because it depends on the tab order. I sincerely cannot understand this and feels confusing enough to stop using Safari altogether!
I hope you are correct. And now that we can change our default browser on all our devices perhaps Apple will rethink Safari rather than risk users switching to something else.