OK played the rest of PBs turn and bad RNG luck continued unabated.
I attacked Tabriz killing 2 vMuskets and wounding 3 more before the first rMusket appeared. I lost 3 Cavs in the process, so I called it off. I landed the rest of our troops. next turn I will add the wounded Cavs to 2 off the Armies to allow them to heal and spend a few turns nabbing stragglers.
I would try to ship over a settler and put in a agressive Settlement where I let the AI die attacking 2 full strength Armies. In the meanwhile the other troops can go out an attack Mongol cities which should be only lowly defended.
Looking at the whole situation I would actually suggest to wipe out the Mongols completely. remember it does cost us 10 tuzrns of our end date if we do so, but it would allow us to live without the constant flips. My guess is, that it would save more than 10 turns to just wipe them out.
PS: I am standing now at 7-4 kills due to a heroic but finally dead crusader near Helgoland. I gifted the city to the russian, since we will attack there in 12 turns anyway.