I know you said you have tried every drop under the sun, but have your tried systane drops, preservative free? They’re in a green box from boots and they are the only drop that really brings relief. They are like a gel consistency.
Believe me, I have tried every drop and ointment under the sun. You have to tweak what works for you. If you are regularly using drops which I assume you are don’t touch any drops with preservatives in as they can actually damage your tear film. They’re only really for mild dry eye and occasional use.
The ointment and heat actually make mine worse, (but cold can be good for mine) but I alternate between systane preservative free (the vial has quite a lot in and I make it last the day) and then I can top up with the red preservative free drops which I’m sure you’ve already used. Also if you keep your eye drops in the fridge they feel very soothing in the eye and the cold temp is good for inflammation.
You might have a coexisting condition like blepharitis. Again I tried all the foams and creams and they all irritated my eyes even further so now I wipe in the morning and evening with garnier miccelar water from boots. It seems to really clean my eyelids as mine get quite oily.
It is a lot of trial and error. I once seen an optician who really suffered and she said it can take the tear film a long time to heal and she had personal experience of it. Mine are 100 percent worse when I am stressed and when it initially came on I was going through an unusual amount of severe stress. So there may also be a bit of a link there.
I hope you manage to find some relief, I use drops every day but they only usually get really bad now late at night when they really dry out and obviously computer work is incredibly irritating. It’s a very frustrating thing to live with, but it can be managed. It just sounds like you are in the acute phase at the moment which can last for many months but don’t give up hope.