I've already done my share of "google", but it's still not clear to me, what settings I need to touch to make my Android TV visible on chromecast devices.

I have an Android 7.1.1 on both devices, both connected to the same wireless AP (MikroTik hAP RB951Ui-2nD).
I'm unable to locate "wifi clients isolation" in my router Wireless setup page (that seems to be the main showstopped for various **cast technologies).

To enable communication, just enable default-Foward:
You can do it in the GUI or via Command,

That one is enabled.
I'll have to do some log digging then to see what packets are dropped.

Check drop rules in fw first.

I have 2 Chromecast devices at home, didn't have to do anything special to make it work.

I've tried to disable all drop rules with not a sign of success. Will have to investigate more thoroughly once I relocate the router to a new place in the apartments.