If you add a second Gmail account to the Gmail app, it automatically logs you into every Google service system-wide and starts syncing crap. You can turn off the syncing, but it still pollutes interfaces lists (like calendar) with stuff from that account, spams warnings about "sync disabled" and adds extra account selection steps to certain processes. Is there any way to add the account to Gmail only?

I have been using Microsoft's outlook app for my additional Gmail accounts for this reason, but after enabling 2FA on one of them the other day, I cannot get that account to log back in (the 2FA part works fine, and I get all the way to the last permissions screen, but after tapping Accept, it just hangs on "authenticating with google" indefinitely). Gmail on android is also the only one that lets you get audio notifications for every message*.

*Side rant: Why is it only the Gmail app (and specifically the Gmail app for android, because iOS Gmail doesn't have this option) that allows you to force notification sounds for EVERY message. I'm not talking about priority inboxes (have that disabled). 

The outlook app's behavior, and the Gmail behavior by default, is to notify you for the first email message and then be silent for subsequent messages until you read or dismiss the notifications. I suppose they think this is a smart way to prevent excessive notifications from sounding off, what what it also is, is a recipe for missing important emails. If you happen to not hear the first sound, you'll miss every message until you pick up the phone. You have to then be constantly looking at the phone to check for messages, which is exactly what notification sounds are supposed to avoid. 

So the Gmail app for android has a "notify for every message" checkbox to force it to play a sound for every message without exception, solving the problem. How is this fundamental feature not in every mail app?