Church of Jeff@fembot -- I have not run my own Mastodon or other Open/Fedi server so I cannot give specific examples on that side...
However, as a former sysadmin, generally, YES, administrators have access to parts of the server the regular user simply cannot go. They have access to your email, data, login times, and even location data with mobiles, etc.
SysAdmin stalking has been an issue on every college campus with a computer science department, especially if they have student employees running things.
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