Just to clarify, what Auth service are you using that requires redirect_uri values to not be encoded?
I was doing some research and every major OAuth provider (Google, Okta, Azure AD, Auth0, GitHub, etc.) expects this.
If a service truly rejects encoded query parameters, it is not OAuth-compliant.
For the checkbox under Advanced Options that checkbox does not mean “send raw characters in the URL” — because that is not possible in a valid HTTP query string.
The checkbox prevents double encoding, not encoding entirely.
If you can give me more details on the OAuth provider and what they expect I can help further, but any resource Auth options using OAuth 2.0 will have to encode the redirect_uri value