I read somewhere that you got "robbed" by someone copying your wallet dats and actually got into your system with teamviewer?!
There are a few people who got robbed that way (search reddit).
It actually seems teamviewer is the culprit here.
Imo someone is bruteforcing teamviewer accounts. The attacker only needs to bypass the loginlimit somehow ...
Don't forget the basic teamviewer password is only 6 letters, so even if you set a permanent login password that is way longer that basic 6 letter pw is still valid.
(the default 6 letter pw can be changed to a 10 letter pw including special characters)
I doubt it's Teamviewer because it increases the amount of time you have to wait to try again after unsuccessful tries but it's possible.
But, you can change the default password's length to 10 characters which includes symbols in Options\Security > password strength.
And you can also disable incoming connections from outside your local network. It also makes windows much more responsive and don't use your bandwidth and of course it's completely safe from the outside (Options\General - Incoming LAN connections > accept exclusively). In this case you can also use local IP addresses to connect for example in shortcuts like this which is pretty convenient:
"C:\Program Files (x86)\TeamViewer\TeamViewer.exe" -i 192.168.1.x --Password doesnt_matter_local_only_password