I’m not the best person to comment on this, but I have been trying to familiarize myself with the more common small cyanolichens (which for me has not been easy). My guess is that it could be P. muscicola, but its hard to say with only the information and photos you have posted. From the photos I can’t tell if the spores are really 1-septate (several times I’ve been fooled on this). (A bit puzzled by the precision of your measuerments.) Dry steppe might be an unusual habitat for this species. Posting a photo of what I think is P. muscicola.