I have found a way to have Exchange email and calendar support without having to use an app with trackers, and wanted to post here becaues it’s probably of interest to the folks on this thread.
First off, I have never been able to get my employer’s Exchange-based email to work on the stock /e/ mail app using imap protocol (which I prefer). I had been using Bluemail because of this reason, but did not like the trackers. However, I recently found that Purism’s Librem Mail app (available on F-droid) does work with my Exchange email, so I switched to it (I haven’t tried stock K-9, so I don’t know if that works).
Just recently, I realized that I could get Exchange calendar syncing using CalDAVsynchronizer, a plugin for Outlook on my work PC that allows you to push-pull calendar events to-from a CalDAV server. I created a calendar on my /e/ account through NextCloud, and synced my Outlook to that calendar. Then, using the DAVx5 app (on F-droid), I was able to sync the Outlook calendar on my /e/ account to my phone’s /e/ Calendar app. Everything used here was FLOSS! Also, although I haven’t tried it yet, I’m fairly certain you can sync contacts in the same way using the CardDAV protocol. To some, doing this may be obvious, but I was happy to figure it out. Hopefully someone else on here will find it useful!