Combination of reasons: started working for a company that supports both Android and iPhone and got to see a bit more how the sausage is made. Android is a fucking mess - you end up with a header file somewhere saying, effectively, on this chipset from this manufacturer on this version of Android (which will never be updated) do this workaround because it doesn't do what it's supposed to. Our lead for Android had a Windows phone as his daily driver, back when Windows phones were a thing... This issue is probably mostly avoided by sticking to Pixels I reckon, however.

Also, got sick of the utter mess of crapware on Samsung phones - duplicate (Android / Samsung) versions of all the major apps, Facebook being uninstallable etc. - again, stick to Pixels I guess?

But the major reason was probably the Apple Watch - I wanted one, the Android offerings are miles behind, and you need an iPhone for that.