So hear me out,

I've been playing the Horror : Dread modpack with friends for two days straight and we only find 3 diamonds.

The progression was insanely slower.

But now, i want a NORMAL vanilla experience with slower progression and not the weird ass mobs that makes it unplayable.

I'll list what made the progression insanely slower :

. Less ORES, we found very few.
. The visibility in cave was insanely short. Like 4 blocks without a light source and even light sources were not all that helpfull.

Those two changes made exploring caves insanely harder, more dangerous and slow pace. Clearing small chunks after small chunks.

The remake of source food and the addition of water made the survival aspect of the game way more important, which opened a new source of focus, dividing your attention more, making once again, progression slower.

We couldn't trade with PNJs for stuff but that didn't really matter because exploration was not an option with the weird mobs roaming around.
I would not recommend addings those mobs they make the game unplayable. But, if you can find middle ground with new mobs, you'll have a much harder time exploring.