Autodesk Premium reporting API: Is the 3-way auth token the only way to access the usage endpoint?

I'd like to use a server-to-server "app" for automating the update of which accounts get a flex token, and which account get a named user. I need to get the usage from the API, and it looks like it only supports a 3-legged token.

Is it possible to use a bearer token from a server-to-server app?

If not, why not?

The Premium Reporting API provides a PAT (Personal Access Token) exactly for this use case, letting you access their API from a server side, without having a user going through the 3-legged login dance.

The process of using PATs is as follows:

• You generate a 2-legged token the usual way (as explained in https://aps.autodesk.com/en/docs/oauth/v2/tutorials/get-2-legged-token/)
• You generate a PAT (as explained in https://aps.autodesk.com/en/docs/insights/v1/developers_guide/authentication/personal-access-token/)
• You can then call any Premium Reporting API (which typically requires 3-legged tokens) by including the 2-legged token to the Authorization header and by including the PAT in the ADSK-PAT header