At last I managed to watch FIRE AND ASH.
Two conclusions for me:
I would say, the three movies had enough original ideas and story for two movies but with all these dublications and repetitions they managed to stretch it over three ones. A lot of screentime wasted.
Secondly, in the third movie I thought like in the two previous ones I found the score much better if they had left out the choir. With this, its awful religious connotation and pseudo ethnic coloring which makes no sense for extraterrestrials it permanently feels over the top and just adds a cheesy tone to the images.