The bigger problem with GMail is that the mobile app has no controls to manage large amount of emails - not even a basic 'select all'. Which is hilarious, because Inbox was so good because it was easy to manage most of your email on your phone.

Now my Gmail is overflowing because it's too difficult to archive thing I want, or delete what I don't in bulk. I actually have to log into the web interface to do any kind of clean up, which is something I never had to do with Inbox.

Just use a proper desktop client. Gmail's IMAP implementation was pretty non-standard last time I checked but it should be good enough for this.

what's hard about that?

When you are approaching your limit they give you a warning and link to this: https://support.google.com/mail/answer/6374270?hl=en

Had no idea you could do that. Thanks!