It's a little odd to complain about infrastructure (SPS, EX) then go discuss UX (Outlook) as some sort of example of said infra (?!?) and then go to discuss _cloud only features that never existed on-prem_ (M365 Groups).
Before complaining, learn.
Before complaining, learn.
You don't have to understand the backend to use their tooling.
Outlook == Exchange == O365; in the same way Gmail == Web & Service.
Complaints about the ecosystem of products (that incentivise their use and in some cases aggressively lock other tools out!) are all valid when complaining about an ecosystem.
Only pedantry need delineate them from each other, they're inextricably linked.
Outlook also comes in a few different varieties which are oddly not the same.