Sounds like you need an old school email client. May I suggest gnus?

Many, many places (even academia, not just businesses) only allow Outlook to be used as an email client "for security" these days -- they actually go out of their way to disable POP and IMAP access and even use Microsoft's authentication system to get access. I've been using email for close to 40 years at this point, and I actually did use Emacs as my e-mail client in the 1990s, but that hasn't been possible anywhere I've worked for close to two decades at this point.

Thunderbird supports what Microsoft call "Modern Authentication" for MS365. I'm not sure if that's enough, or if the administrator can still block Thunderbird.

Unfortunately, emails (at least in my context) are rich text, and they pretty frequently include images that I care about. I don't think gnus can handle that, given that it looks CLI-only.

But also, it looks like I'd have to do some substantial elisp work to get filtering, etc. working. This is starting to sound like way more work than hitting Ignore on a Slack thread. Maybe it's great once you get it set up, and assuming nobody sends you rich text where you care about the formatting?

And there is always at least one person in email chain who puts their signature with company logo, custom fonts and colors to every single reply, making it annoying to try follow the conversation because my email client can't even parse the mess anymore.

Thunderbird can do this, although I haven't used it myself.

(And I realize not many people use Thunderbird for work.)

https://support.mozilla.org/en-US/kb/ignore-threads

I just installed it today because I was tired of apple mails mandate that I must block remote files 100% if the time (forcing me to click each time I want to see "load remote content") or let every random email I receive and preview have user tracked remote content (or the zero click bad stuff..). Thunderbird is much better at making this a balanced approach that's works well for me!

MailMate is a great option on macOS.

Agree, it’s great. Only disadvantage: no “Dark mode” for email content.

Thunderbird has the Dark Reader addon, which is very nice…

Email filters me son.

OK maybe I don't know how to do this right. I do that for automated systems, but do you filter entire conversations? Like, I'm on some random email thread, and dozens of people are replying. Making a rule feels pretty heavyweight and isn't quick (at least in Outlook).

If I have to, I have to - if it's going to persist for days, I don't want that noise.

If you use Gmail, press m to mute a thread. That's the equivalent.

It's a godsend, I can't imagine an e-mail client without it.

Filter all emails CC-ed to you—label them and mark them as read. You can go through them real fast on Fridays if you missed anything that needs your attention, but most do not (they cc-ed you). If you missed one and someone asked why, well, it was not addressed to you directly.

I hope this is an acceptable compromise.

For some reason the most annoying discussions I am in are not in channels but in "group direct messages". Lots of them have 5+ people and spam discussions that are completely unrelated to me. There is no leave button. Muting is problematic because they have no topic and in 2 months if the same person wants to message a group of people, it will reuse the same group DM for a different message (eg. one month it's about if we have pictures of dogs to share for the internal blog and the next it's info about something urgent from HR).

Oh gawd the worst. Where I work was acquired, so there’s a mixture of Slack and Teams. Because Teams threading sucks so much, people there get in the habit of doing everything in group DMs.

It’s as bad as emails.