Questions about administrator rights

this is a general question.

If I create a Windows user called "abc" and then, I assign an "administrator" rights to him, however, I disable his RDP Access to the server, do you think that "abc" can still do something remotely?

I just want to know whether an administrator without RDP rights can cause problems/issues to the server (such as he can plant malicious scripts, etc)

Please advise and thanks for all the advises