Exactly... Outlook by Microsoft is notorious for being very heavy handed with emails, requiring sites to put warnings to users to whitelist their domains so that they receive invoices or notifications.
At this point with outlook it’s pretty much guaranteed that any important “you just paid a ton of money here is the asset you bought” email (show/bus/etc tickets) will go straight to spam. I check spam before I look in the non-“Focused” inbox.
If I send an email to some business, from the Outlook UI, and they reply, Outlook usually classifies the reply as spam. It’s hard to imagine less spammy email than that.