If you don’t mind doing some tinkering, look at LineageOS. They support a large variety of phones and even provide updates beyond the original manufacturer. For example, I use the OnePlus 7T, which officially only supports up to Android 12, but LineageOS supports Android 14 now. The flashing process is well documented, and you should be able to get through it with only the knowledge of running commands in a terminal.

They do support Google apps by default, but if you’re feeling extra, you can install Lineage for MicroG instead, which replaces the core Google services with an open source one that mimics the original with much better privacy. Most apps do work with it, although sometimes it can break things, such as embedded maps and paid apps that check for licensing. I find that most of my apps can be replaced with open source alternative on F-Droid (an open source exclusive app store) that either are compatible with or don’t require MicroG.

I’ll also mention GrapheneOS. It’s another privacy Android OS with some distinct features. It only works on Google Pixel phones, but it is much easier to install (it uses a Web GUI and automates a lot of the process). It’s killer feature is the ability to run Google services in a sandbox, meaning that Google doesn’t have superuser permissions on your entire phone, just in that sandbox. So put all your Google-required apps in there, and Google can’t touch anything outside of it. I haven’t actually used GrapheneOS, so please correct me if I am wrong about any of this.

End of article. I hope this wasn’t too overwhelming.

Edit: One more OS I should mention is /e/OS (yes, the name sucks). It tries to be like Apple, both in interface and provided services, although it doesn’t force you to use their services like Apple. It’s based on LineageOS, although they do more work than them to remove Google stuff, including using MicroG. This is the one I use, but I am considering switching because it’s been kinda buggy for my device specifically. They provide a GUI installer.