Probably just testing for some vulnerability. If you’re current on patches, you can just disregard as background noice. If it really happens a lot, setting up something like Fail2ban would be useful.
Edit: A quick google search suggests it looks like a Windows Remote Desktop packet header. So something scanning the internet for machines with open RDP

























As a side note, it might be worth it to remind everyone not to accuse others of using AI without clear evidence. I remember seeing one instance of that happening here recently, and it can be highly demoralizing for artists to be wrongly accused.