Posibility to merge two OpenWRT Router into One?

the simplest answer to that question is no...
(but feel free to search the forum for topics about android apps and remote commands and whatnot as at the lower levels these are all relavent but will lead you to no practical solution)

in practical terms... you looking at;

  • remote ubus/ssh/cgi calls and data parsing / formatting / display
  • snmp / netflow
  • prometheus and whatever that other thing is called

out of the box... the only simple thing that comes close is;
and it's multihost abilities...