Android is quite mature now so not sure why people expect a drastic UI change just for the sake of change. A lot goes on behind the scenes in terms of security and bug fixes, along with other minor quality of life changes. On my s23 ultra the phone feels a lot snappier so I’m quite liking the update. The new font is actually refreshing to me, just enough of a UI change to have that new update feeling.
This is most if not all companies with putting ads on their home page. It’s nothing new and been this way for years. So if you’re never buying another Samsung, you’ll find the same stuff on LG or Sony too.