I am a bit confused on how this works and have a few questions.

Do expert level chests and master level chests have the same loot pool?

Do like bandit chiefs or grunts have the same loot pool?

Would a chest at the start of a cave/dungeon etc have the same loot table as one at the end?

Could I somehow save before a chest and keep trying for the best loot?

Thanks for helping!

Chests are random. You can get a novice locked chest with decent loot and you could get a master locked chest with a lockpick and some gold.
You can save before entering a dungeon and the loot might be different (I haven't tried it) but if you save while in the dungeon it will be the same loot.

"Boss chests" usually have better loot than common chests. Naturally these are typically found at the end of a dungeon.

Any container contents (including npc) has nothing to do with the difficulty levels.

^^This right here, along with the chests

I have found the chests are just basically a lucky dip irrespective of the lock difficulty.

Thanks for the help, I found out if you save right before a dragon dies you can change the loot endlessly

I think higher level chests generally have better loot, but not always.

It's really random, generally the harder locks contain the better loot yet one time I came across a master locked chest that was empty...I saw it was empty before I picked the lock but I felt compelled to pick it any way to be sure

I also found 2 gold in either an expert or master locked chest before.

Oh yeah I know how you feel . What I like to do for loot at lower levels is use become ethereal, run into giant camps and pick the lock, and run away with their stuff before I get launched a couple thousand feet.

Interesting approach, I see it as that I have to kill the giants to claim their prize...especially since they tend to carry some decent loot and coin on their person (what giants need gold for is another matter).

OP have you heard about the magical invisible chest in Dawnstar?