Hi there @anthonys welcome to the community!
The M2M token quota is per token created and not per request - You will want to do some sort of caching on your end to make sure you aren’t using too many. Important to note that tokens created for Auth0 APIs are not counted in this quota. Please see this post for details:
Yes, M2M applications created count towards your application quota.
M2M applications are included in your overall subscription application limit and aren’t unique from SPA, Web, Native applications, etc.
Yes - You can use the Management API to achieve this: Auth0 Management API v2 We also offer a CLI as well.
I think this about covers everything, but you may want to reach out to our sales team just to make sure!
Hope this helps!