Limit number of sessions (like Netflix)

I want to limit the number of sessions for user the following way:

• The user can only connect to 4 different devices at a time.
• In order to log in to a 5-th device, the user will have to logout from one of the currently connected devices.

I searched for a SAAS solution, and couldn't find. Searched for NodeJS / Passport libraries, and couldn't find.

Then, I came out with the following idea:

1. The DB Unique Key for user would be JWT Token + Phone Number.
2. The user will connect using OTP (One-Time-Password) with its phone number.
3. I'll save the JWT Token and the Phone Number.
4. If the 5-th user wants to sign-in, I'll check whether there are already 5.
5. I'll remove the JWT session on Logout button click.

So, I have 2 questions in this case:

1. Are you familiar with a possible, known solution for my situation (SAAS / Library)?
2. Is my solution legitimate? I only see 1 problem - If the user doesn't click on the signout but rather deletes the app / the browser data.

Thank you very much!