I have set up Sentry for Micro Frontend based on the docs. However, I can see performance metrics only on the core project. Can I route spans like I can route errors?

Currently, we unfortunately do not support performance monitoring for micro frontends. You can read more about this on this GitHub issue.

In the meantime, the best thing that can be done is to have your performance metrics only on the core project, which is what is most likely already happening.