I no longer have possession of the Mac but it seems someone is accessing my account
Cancel access to the mac
Cancel access to the mac
Follow the suggestions in this article:
If you think your Apple ID has been compromised - Apple Support
You can delete all data on your Mac by using FindMy IF you had it active.
Apple has no way of tracking your device and their software solution to stolen devices is an active FindMy.
I no longer have possession of the Mac but it seems someone is accessing my account