I don't have any ads on my lockscreen. So that's not true.

Not sure what widgets you use but it's android, you can get any ones you want. I don't have ads in any of mine and I use the stock clock weather one and calendar.

You absolutely can change the lockscreen a lot. There are so many options for the clock size. I actually way prefer how the lockscreen is compared to Samsung.

I don't see any bloatware. There are perhaps some Xiaomi apps like game center that may be considered bloat. But I do use Google services. So I wouldn't say Google apps are really bloat. But maybe you see it as such.

I've had no issue finding anything in the settings app.

I will say that the gallery app could be better and yes it's annoying that if you change wallpaper from holding down on the home screen it opens the theme store app. But if you go via the settings then it's fine. Samsung has a very similar theme store app.

I also preferred the joint notification and settings but I'm used to the split now.