Unblock a specific sender's email

I'm accessing my email using the classic Outlook app with a Microsoft 365 personal subscription on a Windows desktop PC.  (I also have a business email using my employer's 365 business subscription in my Outlook app.)  I accidentally blocked a sender's email address in the Outlook app.  Even after undertaking all of the following actions, I am still not receiving emails from that sender:

1. Checked my spam folder for the sender's emails
2. Removed the sender's email address from both my Outlook app and Outlook.com blocked senders lists
3. Added the sender's email address and domain to both my Outlook app and Outlook.com safe sender's lists
4. Added the sender's email address to my contacts
5. Checked for any rules blocking the sender's email address
6. Disabled rules to see if a rule was blocking the sender's emails
7. Created a rule to send the sender's emails to my inbox
8. Repaired the Office applications
9. Searched for the sender's emails using Outlook's advanced search options
10. Successfully sent an email to the sender's email address
11. Verified that Focused is turned off
12. Reset my inbox filter
13. Cleared my Outlook cache files
14. Enabled automatic inbox refresh
15. Verified that automatic send/receive is enabled
16. Disabled all add-ins
17. Repaired corrupt Outlook .PST file with ScanPST.exe
18. Repaired corrupt Windows 11 user profile by changing ProfileList registry keys
19. Repaired corrupt Windows 11 user profile with other utilities
20. Reinitialized my apps by running AppXPackage PowerShell command
21. Deleted affected email account from all mobile devices
22. Deleted all mobile devices from Outlook

Things I haven't tried yet:

1. Rebuild .ost file
2. Create a new Outlook profile

Also, I discovered that any alias I created as a workaround that contains my last name in it (as does my primary alias) are also being blocked by the Microsoft server for some reason, but an alias without my last name isn't being blocked.  The sender's tech support has confirmed that the sender's emails are in fact being sent and are shown as being delivered to me.

A Microsoft Outlook.com support agent told me that Microsoft needs the SMTP logs from the sender as the only way to diagnose the problem.  However, the sender is a major financial institution and the sender's tech support told me they will never release such info due to security issues.

I'm being bounced back and forth and back forth between Microsoft's Outlook.com support and Microsoft's Outlook web in-app support, each say the other team can fix this issue.

Has anyone else ever experienced this issue and fixed it by doing something I haven't tried yet?