Sadly, it depends. Many manufacturers have deals in place with Facebook, etc to prevent the un-installation of these apps. At best you can "disable" them completely, achieving the same effective result. Any downloaded updates to the app will be removed and it will be _supposedly_ incapable of running in the background. I suspect however that there are also other e.g. Facebook services running in the background that need to be explicitly disabled with Android running in developer mode.

This isn't a problem if you have a rooted device, but root is difficult/impossible to obtain on certain devices (like Samsung's Galaxy 8 onward) due to enterprise level tamper-proofing.

Having said all that, I just got an unlocked Pixel 4 and it has zero of that bloat. If you happen to consider the Google services themselves bloat/tracking (they often are), rooting is fully supported which allows you to install an Android distribution without any Google services.

Unfortunately it's complicated. There are many OEMs, and each configures things to their liking. Then there are carrier branding deals which (often) result in per-carrier customizations on top of that.

Typically, "uninstallable" apps can be disabled via adb commands if you don't want to (or can't) flash a custom ROM. Sometimes they can't however - for example, Amazon sells subsidized phones that display advertisements on the lock screen.