If you’re (going to continue) using Office 365, you can use Evolution as an Outlook replacement. Evolution EWS rides OWA and ActiveSync protocols to give you email, calendars, contacts, notes, etc. I’ve used it for over a decade. It works very well once setup.
As for Android, there are several, including Outlook for Android (which is bloated and slow, being a Microsoft product), which I am forced to use because of our company SSO config.
If you’re looking for an Office 365 replacement, I use Nextcloud for my personal stuff. It has files, contacts, calendars, notes, etc. If you install the OnlyOffice plugin, you get multi-user online document and spreadsheet editing. I use the DAVx5 connector to get (shared and personal) contacts, calendars, and tasks in my Android phone. It integrates into the environment so all calendars and contacts apps work automatically. It also automatically backs up pics/vids I take with my phone automatically.