I can not create comments yet, but if you do not find a better answer than this, or you can not wait until this is implemented in aspire as they told you in discussion in github

Consider creating a local project api that will act as a proxy for you external(s) apis, this will help for other things too (evaluate if you want this project to be publish or just for development).

you in this proxy you can implement strategys as retries, fallback, cache...