How to customize the JwtBearerOptions in WebApplicationFactory without replacing the original one?

[Kralizek]

I need to test some endpoints protected by JWT auth.

In my PoC I was able to get a token generated by the test by modifying the application under test by hardcoding the signing key and a valid issuer in the token parameters.

Now I want to move these changes into the definition of my WAF but I am having a hard time understanding how to customize the existing instance of the JwtBearerOptions class with my test values.

I thought about using the PostConfigure method but I couldn't get to find the right instance.

Any suggestion?