My suggestion would be to use the private app. Create a pvt app and provide all the required scopes to it, all the things that you have mentioned can be achieved using the pvt app. It will create an access token and you can use it to hit the API endpoints. Just make sure that your access token is not exposed; keep it private. In the pvt you have to add scopes that are mentioned in the API doc which you are trying to hit, just add those scope and use the token to hit. As you said, you are a superadmin, so you can create and add scopes to the instance.
I hope this will help you out. Please mark it as Solution Accepted and upvote to help another Community member.
Thanks!