Admin can get all permissions in tableau. Please create another user and assign the person.
This is the highest level of access for Tableau Online.
Unrestricted access to content as described above, but at the site level. Connect to Tableau or external data in the browser, Tableau Desktop, or Tableau Prep; create new data sources; build and publish content.
On Tableau Server, server administrators can determine whether or not to allow site administrators to manage users and assign site roles and site membership. By default, on Tableau Server, and always on Tableau Online, site administrators are allowed these capabilities.
ite Administrator Explorer
Same access to site and user configuration as Site Administrator Creator, but cannot connect to external data from the web editing environment.
Can connect to Tableau published data sources to create new workbooks, and edit and save existing workbooks.
BI, Aspire Systems (India) Pvt Ltd
Whilst the above suggestion is valid, I expect the reason the reason you have set these individuals to site admin is they need access to functions that only site admins have - eg manage schedules, view admin reports. Unfortunately this is an issue. We too have people that need admin rights so they can do specific tasks that only that right allows them, but in doing so it grants them complete access to all content and associated functions, regardless.
I commented on this idea https://community.tableau.com/ideas/4683 which you might want to upvote
Another idea is https://community.tableau.com/ideas/4582
Unfortunately, there doesn't seem to be alot of traction on both.