Best to avoid them until you get the MS but in the case where that is not possible stock up on sundelions and cook them with ingredients to create food that cures gloom and allows you to heal yourself with other food or elixers. It also helps if you have all the vows to assist you in combat, bomb arrows are effective against them and the dazzle fruit can stun them long enough to give you time to give yourself space if they corner or Swarm you.

In all honesty they're probably the most dangerous enemy in the game. 

They are deadly, but easily neutralized once you climb onto a higher ledge.

I think the most dangerous is Gleeok. That thing has an unstoppable agro :O And I didn’t even encounter the ultimate version of it. 

Even on horse I barely could distance it. And phase 2 is such a hassle (though, incredible fight).

Fuck Gleeocks, they make me wish Link could summon a Hyrule Megazord and take off all three heads with a big ass tokusatsu sword.

I just use keese eyes and a bow that shoots multiple shots if I have one. A lynel bow can take all 3 heads out at once.

Good, but they still do a shit ton of damage with most of their attacks (at least the frost one does). Also, and I can't believe I didn't think of it before looking it up, when the Frost Gleeock flies up out of arrow range, that you can get on one of the icicles it drops, use Rewind, ride the icicle up after Gleeock and attack up there.

Really? I've only got 8 hearts and two-stage clothes upgrades and I've killed a couple swarms of Gloom hands. Ice and Fire Chu jellys on arrows did it for me, then a powerful spear and careful dodging on the second phase. I won't lie I definitely burned through a couple sundelion meals each time fighting them, but they don't wreck my shit the way the only Gleeok I've encountered did.

Fighting gloom hands in close combat is not recommendable.

I've found and killed King Gleeok yesterday on the third attempt. That was fun and challenging and a nice twist on the standard gleeoks, but the second phase was easy as soon as these icicles dropped in front of me I knew what to do and brought him back down quickly.
Also beat a frost gleeok. Now I just need to beat a flame gleeok, but the only attempt I did so far I got literally nuked in the second phase.

Fashion of the Kingdom or Threads of the Kingdom whichever fits better. 

https://youtu.be/adBaO1qRr6A

Some combat highlights. 

40 hours in and I feel like I finished 20% of this game at best

So far the only places I liked exploring underworld were the places close to mountains, those are locations where you can find mines and they have more to explore and interact with. My first chasm was the big one in great Plateau and I landed directly into a mine with lightining, paths and tons of zonai devices. It felt just right, tight and gave me a sense or progress even in the absolute darkness. I eventually arrived in the location Josha wanted me to get trough even before I unlock her questline (I'm yet to understand what exactly triggered her questline, I just talked to her yesterday and she decided to assign me the quest that I already gave finished)

Most of the underworld seems to be filled with void, Lanaryu depths were specially infuriating to explore, as I struggled to find any light roots, 2/3 of the map still missing for that region *sighs*

The rest of the game has been really fun. Over 50 shrines completed and I finally unlocked the sensor. The questline to unlock gear upgrades with the Great Fairies was low-key obnoxious... and that's a good thing! It remembered me Elden ring questlines where I had no clue when they have actually started and what to do next. Only few minutes ago I stumbled in the stable in the woodlands and FINALLY could take the violinist to play to her. 

I also beaten my first Dungeon. The plataforming section to it was really my favorite on the game yet, and I loved how my boy Tulin was with me all the time, MVP in the game so far. It's fun to have his Ghost following me and saving my ass with his bow shots

I think I will try to complete 70 shrines and start my second weather quest. I unlocked all 4, but didn't started any (besides the Rito's I've already finished). Do you guys think it's better to go for Zolas or Goron? I will leave Gerudos for the last.