From the reports I'm reading, I don't think it's isolated to any particular title. It does appear that the titles that are played the most experience this issue the most; so most PS5 owners are reporting trouble with SM:MM. But I think it's because it sells the most, so by percentage you're going to see more complaints about crashing around that particular title.Is this something specific to Demon Souls? I've got three PS5 discs (Valhalla, Miles Morales and Sackboy - with Dirt 5 on the way) and have been swapping between Astrobot, Valhalla and Sackboy quite a lot not had any software issues or with discs not starting up. I have read that Miles Morales was causing some console crashes but I've yet to start it.
Any problems with any other disc-based games?
Nope. I agree with your analogy though. The "most powerful console" stuff, which in my experience was not that prominent, just the odd tweet and mentions on Microsoft's website, could bite them on the arse. Sony, ironically mostly poor comms all year, under-promised and over-delivered. This is generally the best approach.
Demon's Souls when playing has been a fairly rock solid experience for me, not a single issue. Getting into Demon's Souls tends to be where the trouble area is for me.