The first episode of Elden Ring Dissected is here to explain how fall damage works. It has the appearance of looking random or inconsistent, but asides from one particular issue with Torrent it generally follows some pretty strict rules.
https://patreon.com/illusorywall
0:00 Introduction
1:06 Fall Damage Breakpoints
3:20 Fall Damage Amounts
7:13 Dexterity & Fall Damage
9:38 Equip Load & Fall Damage
13:25 Time Spent Falling
17:06 Torrent & Fall Damage
23:10 Killboxes & the Death Cam
25:47 Scripted Locations / Misc
27:20 Closing Words
Here's the wiki page I made on fall damage-
https://eldenring.wiki.fextralife.com/Fall+Damage