Outlook instability on Macs has always been a problem imo. What was most frustrating were the old iOS calendar bugs where if you accepted a meeting from iOS it would spam the entire attendee list with a whole bunch of "meeting accepted" emails. The issue was more topical than anything, but it was a big annoyance to say the least. Unfortunately, there are few systems that are as robust as Exchange at an enterprise level. Yes, there's Lotus Notes and Domino servers, but they're riddled with just as many bugs as Exchange except there's 1/10th the number of articles out there to help administrators. The other option would be to change your enterprise to GSuite, but the administrative options there to either left-click and manually enter everything, or interact with complicated API's.
You mentioned better solutions than Outlook for Mac - do these solutions still support Exchange?