Been trying to find this on Google and honestly wondering how enemy levels work on this game.

Do they scale or are zone set with like a range of enemy levels?

I can tell you how past Beth games worked. Since Fallout 4 uses the same engine as their older titles, I would imagine the game mechanics are similar.

Mostly, enemy encounters are based on leveled lists of actors. As the Player increases in level, so does the level of the enemies generated. Hard-coded encounters remain static regardless of player level. This would include named NPCs the players meets and the like. There are/were also encounter zones. These zones, usually defined in outdoor settings, would take on a level based on what level the players was when he/she first entered that zone. This would remain fixed throughout the game. Therefore spawned encounters within encounter zones would remain at the same level for the duration of the game regardless of the number of respawns.

Hopefully a mod comes out that keeps enemies levels with you. I would prefer not to have the enemies get completely trivial by the time I'm level 100 or so.

The further south and east you get the higher the enemy level, I'm not sure how interior cells work but I'm assuming the same.

This is how it is already for about (I'm guessing) 80% of encounters. Though for many, this will still not be enough as the player inevitably becomes over-powered. For example, I found in Skyrim, that at high levels, my player could slay a dragon with 2 arrows. I modified the game for myself (not a public mod) that boosted dragon health by a factor of 10. Then basic dragons went form 400 Health to 4000 and ancient dragons had over 12,000 health. Now that was a battle.

As an alternative, if the game is too easy, just ramp up the difficulty level. You don't even have to start a new game.

Yep, but it doesn't only progress by location, once u climb the level ladder u gonna face more deadly types of enemies.
I'm currently getting past 60 and having some stronger and differently named stuff around.

Not many, but something at least.

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So if I enter the Glowing Sea at level 1 the game generates enemies to match my lvl 1 char and keeps that enemies level even when I'm level 100+ and enter that area ?

From what I gather zones don't get set at a level when you enter them. They have a strength range which the enemies will be to one side or the other of relative to you. If you're over they're at the high end if you're lower they're in the low of their range. I think there are still other places that are always on the high end I speculate or heard something about. You can also raise the difficulty anytime so once you have power armor and all this cool stuff, you'll have to use every bit of it to survive.

Enemies give more exp, are higher named like ghoul stalker punisher death face or something. People seem to have better upgraded armor and guns too.

So I did some testing using player.setlevel.

From what I can tell certain zones have set min-max levels enemies can be.

This map

http://nerdist.com/wp-content/uploads/2015/11/Fallout-4-Map.png

seems correct on that subject, and by setting my level to 150 the areas that are set never go above that level.

Ex: Concord has a level range of 1-4 and enemies will never go beyond that.

Ex:Glowing sea have a level range of 30+ so any enemies found in the Glowing sea will be minimum of 30, but can spawn as any ranked enemy higher than 30.

Also from what I found, those zones also have a greater chance of spawning the endlessly scaling enemies that match your level.

Most ghouls in the Glowing sea were charred feral ghouls which are level 62+ and at level 150 the charred ghouls were all level 150 with some gangrenous feral ghouls mixed in, which according to my guide are level 42 and certainly these were 42.

So using the guide and testing it by level it appears the zones have a level range, and the harder zones spawn enemies closest to your level range that can be allowed into the zones.

BTW, those level 150 charred ghouls were stupidly hard and smacked you with 15 rads per hit.