How to handle separate authentication for mixed Blazor Server App and Minimal Api

I would like to combine a blazor server app with a minimal api as additional option for users to access data.

The blazor app uses windows authentication:

builder.Services.AddAuthentication(NegotiateDefaults.AuthenticationScheme)   .AddNegotiate();builder.Services.AddAuthorization(options =>{    options.FallbackPolicy = options.DefaultPolicy;});

I would like to secure some endpoints of the minimal api with basic authentication. Some should be freely accessible.

How can I configure authentication for the minimal-api separatly from the blazor-app?