Personnaly, I use https://gitlab.com/shackra/goimapnotify , you can add a `~/.config/imapnotify/{{ youremailaddresshere }}.yaml` config file for each of your email addresses and enable and start it as a systemd service with `systemctl --user enable ---now goimapnotify@{{ youremailaddresshere }}.service`
Here is and example of a config file for a gmail address :