I have stopped getting gmail notifications a few weeks back. Unless I open the gmail app, I am getting no indication that an email was received. I tried wiping gmail data but it did not help. The only way I can get a notification to appear is to either leave the phone on my nightstand overnight, or to untick and tick the "sync gmail" checkbox in the gmail app.
Gmail app settings seem fine as I have compared them with ones on my Nexus 9 running LineageOS 15.1 and my Galaxy S5 running LineageOS 18.1. Both of these get the notifications as expected.
Gmail app does not show background management settings in the app settings so I am guessing it is following a hardcoded option.
How can I fix this? gmail notifications are quite important to me. Thanks.