How to get rid of Microsoft AutoUpdate virus

I'm trying to permanently delete Microsoft AutoUpdate (MAU) and its annoying prompts, but nothing seems to work. I've followed the instructions from https://apple.stackexchange.com/questions/428234/how-to-remove-microsoft-autoupdate-from-macos-m1 and https://apple.stackexchange.com/questions/365290/how-to-stop-ms-autoupdate-prompt but neither one of those solved my problem. I've deleted all associated files in the relevant ~/Library/ directories and made sure there are no hits for files when I search my Mac for "AutoUpdate" and the like. Despite of this, the MAU prompts return every time I restart my Mac. When I search my Mac for files again after the restart, I can see that there are two new folders called "com.microsoft.autoupdate2" and "com.microsoft.autoupdate.fba" which are located in the directory ~/Library/Group Containers/UBF8T346G9.ms", which contains another empty folder called "MerpTempItems" and an empty .txt file called "Microsoft AutoUpdate.MERP.params.txt". Even when I delete the entire "UBF8T346G9.ms" directory, it returns with the exact same contents on the next start up. Can someone please help me get rid of Microsoft AutoUpdate for good? Edit: my macOS version is 10.14.6 and Office version is 16.54. The entire Office Suite is installed. As for the licence: it says "Licence: Not Activated", whatever that means.