Foreign hackers breached a US nuclear weapons plant via SharePoint flaws

For the Outlook haters out there here's my 2c of anecdata. At home I use BetterBird, at work Outlook, and I used to use Apple Mail/Calendar on my phone. I access multiple mailboxes: Microsoft 365, Google Workplace and Apple iCloud.

1. There is no planet on which BetterBird/Thunderbird is better than Outlook as a mail client. None.

2. I hate having my mail and calendar apps separated, so on the phone moved from Apple Mail+Calendar to the Outlook iOS app. Been using it for a couple of years. Can't imagine going back.

In my experience, the Outlook client provides features I want in a way that is usable across multiple clients. While I use BetterBird on my personal linux laptop (mainly for sync, so I always have a local copy of my mailboxes), I also use the web Outlook client (much more usable).

On Linux I've also used Evolution - not a massive usability difference with the FooBird. If anyone can recommend a combined mail + calendar client for Linux that is polished and power-user functional, and can work well with differing mailbox providers, I'd love to give it a try.