You don’t need to use Google’s vesion of Android. You can use a de-googled Android.
Android is an open source project (AOSP) and there are many custom roms built upon AOSP.
Notable among many are, GrapheneOS, CalyxOS, LineageOS, /e/ OS. The latter two even permit you root access via adb so you can modify your system to your heart’s content.
You will never get this grade of freedom and control with anything Apple.
I will admit I never heard of these so I could look in to these one day. I may buy a cheap device to test this on and see how it works etc or use an old phone from work we don’t use anymore.
I guess I never really knew about these due to lack of interest in phones and a little bit of ignorance on my part as I never attempted to look in to it, and back when I was getting phones I was on Windows so I never really looked in to this kind of stuff back then or delved in to options until I started Linux.
But I will have a look in to these and see what I end up with.
Before buying anything, check the supported devices from any of the projects mentioned. Then you can make up your mind what device to choose.
Also, I believe DivestOS too has support for a variety of devices so it may be worth investigating.
The only phone I’ve seen with ads plastered on is my dad’s Xiaomi Note 11. It is just filled with ads on every single system app, like the File Manager or the Gallery app. Otherwise, no Android phone I’ve used, from small manufacturers to big name ones like Samsung, had ads in their system. Bloat, however, is pretty much guaranteed, unless you go with Google, but it seems that you can easily remove the bloat by using adb.