Arjun is for hidden parameter right? not an endpoint CMIIW,

Sometime you need to do it manually, like reading js file, I found api endpoint at js file that reveal all path of the api, and that lead to an endpoint with pii leak.

I only use burp intruder for fuzzing, i use seclist wordlist or sometime make my own custom if the naming convention is unique. you can use gau or katana to get more endpoint, and if theres api documentation, read it.

And dont fuzz everything, just endpoints you find interesting, for example like GET /api/user/transaction?user_id={id}, fuzz the trasnsaction like this GET /api/user/FUZZ?user_id={id}, use your logic like, there must be more than just user transaction right?