Application-only auth when retrieving users campaigns


When getting campaigns data per user_id should each user login so I can retrieve his token access and then use it when requesting his Twitter Ads data? Or is an application-only authentication is enough for this? Example end points:
- GET stats/accounts/:account_id/campaigns/:id
- GET stats/accounts/:account_id/promoted_tweets/:id

In the latter case, how can I retrieve the :account_id?

This oAuth method is very new to me so any help is appreciated.

Thanks before!