Hello,
What are the requirements for level 94 blueprints to drop?
Does difficulty matter?
Does player level matter?
Does monster level matter?
no, unless it’s a specific blueprint, like deathstalker,
a bit, since things (enemies/areas/containers) scale depending on your level
yes, tho monsters in general is a bad source of blueprint, what you want is specific containers
SR/Crucible chests, Monster Totems/Devotion Shrines, Skeleton Key Dungeon end chest, Nemesis Troves, Treasure troves
^the above will scale to the area you are in, the area will scale to X level + Y depending on your character level, the containers will then spit out blueprints in a certain level range
from my experience you can start getting 94 blueprints already around level 80 depending which area/containers you are getting blueprints from
keep in mind even at level 100 you can still get level 80-84 blueprints since some max level blueprints are just that level, likewise if you are level 100 you will also get the AoM lvl 75 components and certain lower/mid level relics in the lvl 60+ range the way teh game seem to prioritize/“mandate” you get certain important blueprints
Indeed, some lvl60 relics are much better than lvl90 counterparts (Eye of the Storm, for example). Not to mention they serve as crafting materials too. So the game still drops them even at 100 level, so you wont be forced to farm some low-level areas in Elite just to to get those recipes.
Yes, if we talk about endgame lvl90-94 recipes, the type of mob (container) is what matters first. Normal bosses/champions have poor drop rates for those, mosters totems - average, and Nemesis troves/lastboss chests in rogue dungeons/Crucible or Forgooten Realm chests at high waves all have high drop rates.
Do note, that if you get a recipe you already have, it simply vanishes, so your ACTUAL drop rate also heavily depends on the number of recipes you own.