This whole problem can be so easily fixed. Game already can detect if you’re in a combat with another player.
So just instant decline queue that pops up (no need even to show it) if player is in combat with enemy player or was in combat in the last minute (in case they drop combat with vanish/invis/etc). If player has bounty on them - it’s 5 minutes.
Similar for changing a phase.
Just make any queue/phasing work like that, at least for War Mode.
I wonder if anything about it would ever happen, because these exploiters are getting out of hand - I see this happening more and more.