I currently have an end user that is a power user across my sharepoint online tenant. I do not have the access to PowerShell or ShareGate to run permission reports to locate and remove all instances of their permissions. Is there a way to find and remove an individual across my tenant using the SharePoint Admin center, if not what would be a solution other than going into each site collection and checking every list library etc. to remove every instance?
There is no OOTB way to remove access of any user from all the site collections.
If you are going to use this user for any other purpose then you can use PowerShell given in below link. You will need SharePoint-Admin rights to run this script
If you are not going to use user anymore (for whom you want to remove access from everywhere), you can disable that use in Azure Active directory so even if user does have access he will not able login using his account.