Hello guys,
I would like to set up so that I can only log in to mikrotik via one PC, is it possible to set up some mac address filter?
Any ideas?
Thanks.

is it possible to set up some mac address filter?

Yes, it is, but it is also relatively easy to spoof a MAC address if you know the correct one.

Are we talking about wired or wireless connection? The available solutions differ.

wired connection.

In /ip firewall filter, you can match on src-mac-address. Depending how your firewall is organized, you may add src-mac-address=th:ep:er:mi:tt:ed to the action=accept rule that enables access to the management service, or src-mac-address=!th:ep:er:mi:tt:ed to the action=drop rule that blocks access to the management service, in chain input of /ip firewall filter.