Using ITokenAcquirer for non-microsoft oauth provider and custom scopes

[svalbuena]

I have an app that talks with Databricks and I need to fetch an access token as described on https://learn.microsoft.com/en-us/azure/databricks/dev-tools/auth/oauth-m2m#oauth-m2m-manual. I know there is the automatic unified client authentication method but I cannot use that at the moment, so I'm interested on the manual (but automated) approach to retrieve the access tokens.

First, I used MSAL (library Microsoft.Identity.Client) IConfidentialClientApplication.AcquireTokenForClient(scopes: ["all-apis"]) to retrieve the access token and this worked well. Then on Choosing a version of MSAL.NET documentation I saw I could use Microsoft.Identity.Web library to do the same, from what I understood it's preferred to use this library as it's an abstraction on top of MSAL and handles a few more things for you, so I tried using ITokenAcquirer.GetTokenForAppAsync(scope: "all-apis") but it complaints that the scope is invalid and I should use one that ends with "/.default" "IDW10404: 'scope' parameter should be of the form 'AppIdUri/.default'. See https://aka.ms/ms-id-web/daemon-scenarios. (Parameter 'scope')".

I'm confused, is the Microsoft.Identity.Web incompatible with OAuth/OIDC providers that are not Microsoft? For my use case should I just use MSAL with IConfidentialClientApplication?