I am generating access token for each user using OAuth and then making calls to fetch data specific to user. Now I want to fetch data of 10-20-50 users in such scenario should I generate access token for each user using OAuth process and then store each access token of each user in DB? and then use refresh token to refresh it after expiry? My goal is to aggregate data of each user but for that I need to make API calls using access token generated using OAuth. How can this be automated or any other suggestions? What is the general procedure followed in such cases?

Are you running into API limit for calls per user? If not, using same token should be fine.

No for each user I have to generate new access token so 100 users that means 100 access tokens. Each access token is generate using API client id and secret