Alternative to Microsoft Outlook

I recently switched to Ubuntu from Windows 10. I used to rely heavily on MS Outlook, and still do, and I want something similar in Ubuntu.

I need an alternative that provides/supports/integrates (not sure what the appropriate word is) email, contacts and calendars. Tasklist also would be ideal but is not necessary.

I've been using Mailspring and KOrganizer, and while they're brilliant individually, I want something that combines everything under one roof.

Thoughts?

Thunderbird with the lightning extension provides a single application for managing emails, calendars and tasks:

sudo apt-get install thunderbird xul-ext-lightning

You can then install more add-ons, for instance:

• Provider for Google Calendar : to sync with your google calendar.
• Exchange calendar : to sync with MS outlook servers (this version is working fine).

Did you try Prospect Mail ?

This has been considered as Unofficial Outlook 365 Client on Ubuntu. See more details here: https://snapcraft.io/prospect-mail

sudo apt update
sudo apt install snapd

then

sudo snap install prospect-mail