How to choose the final boss in GWENT - Rogue Mage?

[Dmitriy_1981]

Hello. Tell me, please, is it possible to choose one specific boss from the three final ones in Gwent Rogue Mage?
Sometimes you have to restart the game many times in order to get a certain enemy, and this is a bit strange.
The question is related to the fact that the most difficult and interesting boss for me, taking into account the deck I play, seems to fall out less often than the other two. And even if we consider that this is just a subjective impression, it is still not clear why this restriction is needed - that only randomly you can choose the final opponent.

 

[Dmitriy_1981]

And at the same time a related question. It just seems to me, or is there some connection between the final boss and the tactics and distribution of the rest of the opponents on the map? For some reason, when playing as Shani, I not only get the green Gorspeth less often than the snow dragon and the fire demon. But even when it does, the game feels harder, and it's like the final boss is harder to get to than the other two.