Backend been disabled

OK so I know this question has been asked before but I can’t find the answer. I have a clients old wordpress site and I want to export stuff from it. But when I log into the backend I can’t see many of the usual menus including SETTINGS, PLUGINS, APPEARANCE. The profile says I am an administrator but I’m obviously not as when I try to access the Plugins directly using a URL it says “insufficient permissions”

So I can’t find out who set the site up, I can’t change the theme, or settings. I can access the plugins via FTP but there is nothing in there that would disable the admin rights. I’ve tried manually disabling plugins by renaming then via FTP but nothing works. I assume the people who set it up hacked the DB in some way? Any ideas on how to get full admin rights back, or at the very least do an export of all the site content (no plugin available to do that)

Many Thanks