I’ve been told the extended time to open is related to how big the outlook database is, I average 200 emails received a day with various alerts and notifications from internal tools and it cripples new outlook in about a week if I’m not diligent with keeping folders cleaned out/emails deleted. This volume wasn’t a issue before I switched.
They’re doing their best to “improve” excel too… I can’t understand how their AI generated cell fill is worse than the old approach.