You can limit the number of related records by limiting the repeat_count of the repeat section in your survey to 1.
Thanks Deon,
The goal is to be able to utilize the 1:1 pop-up configuration where you can add the actual values instead of the related field count.
Hi T L,
Currently the 1:1 relationship type for existing feature services is not supported. I've created an issue to consider supporting this relationship type in the future.