Using classic Outlook for Windows in business environments
I have found the solution - the spammers have a way to replicate some email addresses on my “safe senders” list and impersonate the sender to bypass the filter. I deleted those “safe senders” from my list whose domains appeared in the message source (find the “view message source” option when opening the spam message to scan for domains of your safe senders) of the spam emails and since then do not receive any junk emails in my inbox! Needless to say, this was a solution I found on my own, the outlook.com customer service and their Tier 2 outlook engineers were not able to help at all despite repeated interactions.