when it's not DNS, it's AI...
Outlook has always been a random disaster. That's a known fact.
That said - for the last year (probably longer), every time I open Outlook, I get a lovely process alongside it called ai.exe -- this little bastard lives in your Office installation folders in both 32 and 64bit locations - and ever since it started appearing - Outlook runs like a dog - eating CPU - going from it's random crashes to more predictable ones (as if that's some form of benchmark, but this is Outlook we're talking about).
I nuke the contents of both AI folders that house this demon - but of course, it gets re-added every single time there's a Windows Update (they don't even have to say "Office Update" anymore). Now there's a scheduled task for deletion - we'll see how long it survives before for MS to start looking for that and disabling it behind my back as well...
PS: Office (and Outlook) doesn't care when it's missing - it returns back to it's "normally unpredictable self" - which is as reliable as it'll ever get - but it's sure not the CPU sucking monster when big brother is missing.
This is a fully licensed on-premise Office 2021 install.
The moral of the story is that everything else has already moved to Linux in one way or another... This is the last one...