Greetings chmct,
It would be helpful to know if this is impacting all four mail accounts or just one. If just one, is it a Gmail account or the iCloud account?
Also, please check to make sure there are no new rules showing Use rules to manage emails you receive in Mail on Mac
“In the Mail app on your Mac, choose Mail > Settings, then click Rules.
To review an example of a rule, select a provided rule, then click Edit. To close the rule, click Cancel.”
Then, let’s have you try marking one of the messages not junk, to see if it goes back to your Inbox.
Lastly, check to see if the junk mail filter is on or off. If the issue is with a Gmail account, you may need to check that on the server side. Change Junk Mail settings in Mail on Mac
“To change these settings in the Mail app on your Mac, choose Mail > Settings, then click Junk Mail.”
Thanks.