Found this useful list in the VG247 review here: https://www.vg247.com/2020/11/23/demons-souls-ps5-review/
The biggest changes in Demonās Souls PS5
You can now send items that would overburden you straight to Stockpile Thomas
Crystal Lizards will not despawn until you have killed a certain amount of them
Draw distance in The Valley of Defilement has been significantly increased
Many NPCs & enemies have been redesigned
Some bosses have been redesigned
Some pieces of armour and weapons have been redesigned
The item duping glitch no longer works
Healing items drop more frequently
You can no longer shoot through fog gates with a bow
Some rare upgrade materials drop more frequently
Healing items now weigh more
New items and armour have been added
The soundtrack is now Orchestrated, and is significantly different
NPC dialogue has been rerecorded
The UI has been changed
You can now preview spells and magic before you learn them
Crystal lizard change is kind of useful, but think I may have missed the first one still :-/ it dropped off the cliff as I killed it and I didnāt get any drops. Expected to get the drops after re-entering the level but nothing there. š