Gmail messages deleted from all accounts I made; All attached gmail accounts missing
 

I've noticed that I have made mutliple aliases and gmail accounts and I've checked them most of them are missing messages. I've even enabled 2fa for most of my gmail accounts and noticed the something or an app got access to my accounts and started eating away some of my mail (even for the accounts with second factor authentication installed). I've started a gmail deleted email recovery process for some of my accounts as well but that didn't do much. I did not have or create a back up prior to these lost emails. If my account was compromised in the beginning, how can I ensure it won't get compromised again? I didn't share my passwords with anyone, and I am the only one that knows and had access to these email accounts. What can I do to ensure this doesn't happen again?

How do you access your email?
Webmail? App? (Native) Mail client?

Googlemail.com, google chrome usually any browser or on my phone. I can't see anyone who would have access to my account. Nobody else in my family accessed my stuff.

The first thing that comes to mind is that your email was accessed via POP without "leave on server" turned on.

Did you set up access to you mailbox via any new means? A different program or device?

No, everything was to my devices I owned, never had POP on.

What do you mean by "missing messages?" Are these emails that you know were sent to you, but never arrived? Or, are they messages that you saw in your Gmail account, and then later when you looked for the message it had disappeared?

Not sure if this is related to your problem:
https://www.phonearena.com/news/Repo...abled_id157274