It's only photorealistic if you use 10-20m DEM, otherwise any mountainous area just feels completely off and unrecognizable (try to fly over Alps with the default DEM, I couldn't recognize anything around Oberstdorf etc.)
Does Montserrat look realistic in FS 2020? I remember how recognizable it was from Tibidabo but I couldn't find it when I was flying around Barcelona last time.
I think it does yeah. You only see its iconic look really well from the Barcelona angle though! I'd have to check as I haven't really paid attention to it to be honest.