Have seen this in a couple of the betas. Some Apple default apps will ask for the Apple app even if you have something else defaulted.
I have not really tested this in a regular release.
I’m not using the beta, I’m using the latest official release 14.4.2.
In Settings > Mail > Accounts > Fetch New Data > (Select your account), under ‘pushed mailboxes‘ do you have the tick icon next to the Junk folder?I got tired of Mail not showing junk mail in my outlook account. I almost missed out on some study groups that were paying some decent coin. I switched to outlook.