Google's a much bigger part of the ecosystem by default. Used to be the Google app store was a selling feature, now Google is integrated into pretty much every device (and has contracts with manufacturers to force that).

It's also, like Shortwavefilter mentioned, much harder to root or flash a devices.

Though the AOSP has gotten better in ways too. It's gotten a lot better hardening, and still is fairly open (e.g custom app stores added one click).

Last, there's still plenty of bloat pre-installed on some brands, but I think that was the case a decade ago as well if my memory is correct.

Honestly I can't think of too many essential settings or apps that'd be a necessity for everyone. Usually I'd say change privacy settings and disabled as much bloat if you're not using a ROM; but that might not be applicable if you're on a work phone. Apps wise, I'd say stick to open source if you can for the basic offline utilities -F-Droid is great for that if you're allowed to install it.