There are a few things that frustrated me when I made the switch, but I was very quickly very happy to have done so.
1. Firefox. Apple does not allow competing browsers to use their own engines, effectively they are allowed to reskin safari and that's it. As a result you can't use addons and the password autofill is not as good. It still works, but you find yourself having to go into the password manager and copy/paste more often. Plus no ublock. That said, I don't seem to see too many ads either way. "Firefox Focus" also exists on the platform, which does a good job at privacy but is not a full browser.
2. The launcher is the launcher, you can't install another one, you just have to get used to how it works. It's not bad and you can at least have a clock widget these days.
3. For the move itself, there were a couple of annoyances. LiE mentioned whatsapp. If you use signal, there seems to be absolutely no way to backup and restore across android and ios, even though you can do that between phones of either type. Also I find myself using signal a whole lot less because it can't deal with SMS under ios, you have to use their messaging app. Which is fine, it's just a change.
In general though, the switch was 100% worth it. The integrations with my macbook are great. The build quality is a world away from what I was used to with android (crack-prone glass sandwiches that break in your pocket, even in the official case.). And while I kinda have the upgrade itch, my iPhone 12 Pro is actually still pretty damn good, so I'm going to end up keeping it for longer than I did with androids.