I wore my Ultra 1 and Ultra 2 exclusively after years of Apple Watches. I got a Series 10 last year (42mm), and I have to say that I had forgotten how pleasantly comfortable and nice looking the Series watches are compared to the Ultra.
I did adjust to the Ultra and it became normal feeling to me, but it’s noticeable if you go between them.
I got a Series 11 so that I could give my wife my Series 10, and she gave her Series 7 to my daughter. I’d planned to trade in my Ultra 2, but I’m torn about keeping it still for days when I do longer tracked activities. The battery life and action button and such are just nice to have at times.
That said, I think you will adjust to whatever you get, but the Ultra is unavoidably bulkier and less comfortable with some scenarios.