Please help us help you and fill where relevant:
Your LimeSurvey version: Version 3.15.9+190214
Own server or LimeSurvey hosting: 
Survey theme/template:
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I am passing on the responsibility for Limesurvey in our research group. I have now created an account with super admin rights for my successor. Can I remove the super admin rights from my own account and keep said account as a normal user? Or can the new super admin remove my super admin rights?
Thanks for your help! Cheers!

As far as I know, if you were the original super-admin during installation, no that cannot be changed.

That's correct. You need to create a new account for yourself, if you which to have less permissions. You might submit feature request as well.