I fuse my arrows with eyeballs to stun each head, use a charge attack with my strongest 2-hand weapon, and dodge the other attacks. Always use 3x attack up, wear the appropriate elemental gear to nullify attacks, use the sages for extra attacks/distractions. They can be pretty easy if you pay attention to where they are and recognize their attack patterns. Like when their health gets low and they fly up high to unleash a massive attack. That takes time so you need to get up there and take out their heads before it's too late or take cover.
Edit: Also consider fusing the stone slabs. Two long ones 90 deg to each other and a corner one to make a roof that's high enough to just Ascend through. You can hide behind it to sneak up to them, use it to get bullet time, and use it for cover.
There are auto builds without Zonai parts at all, like particularly an instant scaffold that is perfect for fighting gleeoks. I want to say that the simplest one is 9 or 12 zonaite.
That said, I tried using it once but my timing was off and it fell down so I did the entire fight from the ground using a 3x lynel bow with keese eyeballs fused to the arrows. It wasn’t too bad at all, as it was a frost gleeok and my snowquill armor is level 3, making its attacks largely ineffective
For the bow, the Lynel bow is the best, but a Demon’s King bow may do too
To enter bullet time: find somewhere to ascend, or deploy a portable platform (autobuild), or a Hover Stone. The Hover stone can be attached to an arrow, and shot on top of link, and is also a good elemental shield, manipulated with the ultrahand.
While in bullet time, attaching gibdo bones is an effective attack, just aim for the eye on each head. If the gleeok is too far away, an elemental keese eye is a good option.
Have your friends with you, so they can help too.
Just doing that (bullet time, arrow to the eyes, hit it 3 or 4 times while on the ground, ascend and repeat) you’ll be able to defeat any gleeok.
I’m not a good player and I can beat any gleeok in the game that way.
I used springs with preferably stakes attached then a crap ton of eyeballs + lynel bows. Almost died a few times but I managed to defeat them like that
You can use an octo baloon shield instead of spending a rocket.
You can parry the lasers but since they are continuous, you end up getting hit after the parry and you don't reflect them back.
The best damage combo once it's down is to be at 1 heart or less with a molduga jaw knight's claymore, Evil Spirit armor (Phantom Ganon) or Radiant armor (glow in the dark skeleton luchador), and attack lvl 3 food. This allows you to kill it in 1 cycle. I think the base damage of that sword is 128 displayed, the armor multiplies by 1.8 (cause the jaw is considered a bone) and the attack buff by another 1.5. This assumes the sword has the attack + modifier and is pristine.
I farm up a bunch of keese eyeballs (shooting a bomb arrow at a cave swarm makes this easier) and use those to target the heads. If you have fire/ice eyeballs those do elemental damage against their opposite types of gleok heads. If there's an ice gleok head, you can use recall on the ice spike things during the last phase to get closer, but for the other gleoks I usually just keep trying with eyeball homing arrows until they hit.
Ooh. I usually use a spear when they come out. Im rarely quick enough so normlly dont get more than a few. Cant believe i didn't think of using bomb arrows. I have like a 100 to spare from scouring the deapths
Rocket shield, spring, fire + pinecone... Any way to fly. Let loose guided arrows or gibdo arrows if close enough. Two handed charge attack while down. Final phase depends on the gleeok. Lightning immunity helps on some of them.