How to enable author bio & Related Posts in DISPATCH theme?

That looks like your just outputting static HTML for the Author Bio.
Until GPP 2.0 is released which will allow you create a Dynamic Author Block Element you would need to use an Author Box plugin.

GPP 2.0 is currently in Alpha for testing only:

https://generatepress.com/introducing-the-gp-theme-builder/

Then disabling it as it is.

Is this topic now resolved ?

yes.

Glad to hear that