Hi @Anonymous :
Could you tell me:
- What is varUserEmail's value?Is it a user's email address stored as a string?
- How many records are in'CPQ Radio'?
I assume varUserEmail is a user's email address.
Firstly,this formula cannot be delegated.
In order to avoid delegation issues as much as possible, I suggest you adjust the value of data row limit for non-delegable queries to 2000.
Secondly,'Created By'.Email can not be used as a string.
I did a similar test and the following error occurred:

Finally,please try:
Remove('CPQ Radio', Filter('CPQ Radio', varUserEmail in 'Created By'.Claims ))
Or
Remove('CPQ Radio', Filter('CPQ Radio',"i:0#.f|membership|"&varUserEmail = 'Created By'.Claims ))
Best Regards,
Bof