Outlook on the desktop is pretty much in maintenance mode only and Microsoft is already breaking it[0]. As for web version runs on linux just fine so you are in luck.

In general, unless you need advanced Excel features, you can switch to linux.

[0] e.g. https://www.neowin.net/news/microsoft-cant-help-break-window... and couple others

We use Exchange on-premises, and the web client is really bad.

While email is asynchronous and I can live with not seeing it all the time (I check it occasionally anyway), the calendar feature is a must, and specifically the reminders. This is why I cannot live without Outlook launched, and it reminds me of meetings I would miss otherwise.

Didn't expect onprem since microsoft has super weird requirements on it since v2019 and haven't properly maintained it for years (except now you are also supposed to pay for it monthly), but if you would suffer with the old web version, you may want to look into Evolution+ews which should be able to handle onprem exchange on linux. Unsure if it supports niche features like public folders but the normal stuff should be covered.

Have you tried Thunderbird recently? It's had quite a lift.

No I have not, for many many years. The calendar is the key feature for me - I will give it a try then

I just installed Thunderbird yesterday, and it finally supports my work email flawlessly, and even the calendar works essentially the same as with Outlook.

Are you connected to an Exchange server?

We use 365. It says it supports on-prem Exchange as well, but I haven't tried that.

And the crazy thing is that while outlook is my life it's also unbelievably bad. Why can't I have the calendar and email client open at the same time? Why don't newly received email addresses appear in the valid auto complete for sending out calendar invites? Why is search practically useless?

Outlook in its recent versions is (barely) functionally just the repackaged web version.

It is the poster child for enshittification.

Can you briefly explain what it is that you like about Outlook? I've had to use it at corporate clients, and I really detest it. The interface seems to suffer from that same ribbon-nonsense that Word suffers from. Its search is poor and slow. It offers very few display customization options. The calendar in particular is horrendous, I can't even seem to select a time block by clicking/dragging the way I've been able to do in Thunderbird for (probably) 2 decades.

Or maybe you're talking about needing Exchange integration? I don't know what the state of that is on Linux these days.

Two reasons: integration with Exchange and a need for the calendar to be always on (as opposed to email). I need it to inform me of meetings.

The integration to Exchange is key as well, I need to have access to rooms, PSTs etc.

Evolution is a good MUA/calendar/contacts/notes app.

I see it has a connector to MS Exchange. Have you maybe used it and have some feedback?

I use Evolution daily for decades, but have never used Exchange before, so not sure about the connector.