ThirdNerdWhat exactly is considered "vanilla" Minecraft?
DudewitbowIt depends on context. When speaking specifically about gameplay, vanilla Minecraft to me is anything that doesnt modify how the game functions, or add any addiional blocks, so performamce mods and texture mods still retain the vanilla gameplay experience.
In terms of hard vanilla, would just be a stock install, no adjustments.
Well your first definition is opinion based so all good.
The second one is imprecise, as a setting is an adjustment and not out of the range of vanilla Minecraft. Texture packs and data packs are often considered vanilla as well, so no “adjustments” at all is indeed a little hard.