I am so sorry you are suffering, misunderstood and isolated. It must be terrifying with it being something new and still so much unknown. My heart goes out to you. Hang in there, things may improve over time and with more research and understanding, and making the Doctors and general public more aware. There will be better support and understanding.
Many of us with autoimmune disorders and post viral illnesses, ME/CFS, Fibromyalgia, Lyme disease, etc that wiped our prior self abilities lives out with the suddenness and magnitude like being hit by a frieght train.
It impacts on every area of your life and relationships, and people just don't 'get it' and can minimise your suffering and make ridiculous comparisons when they compare your utter exhaustion, weakness, and fatigue and brain fog to the ignorant and infuriating comments saying we all get tired, or debilitating pain is put down like it is general aches and pains of getting older. Even people that knew us before the illness don't grasp that we were physically capable, healthy, strong, fit and worked hard, kept fit etc and suddenly you are seen less than or like a misery guts who constantly complains or is being overly dramatic attention seeking and being a hypochondriac, because everyone around you, friends family, collegues tire of seeing and hearing about you ALWAYS so unwell yet you "look fine" and are even more convinced when they hear from equally ignorant and uninformed Dr's that because all these scans and blood tests etc keep coming back all clear. So it must not be true. These outdated Dr's i.e. The arrogant dinosaurs that are set in their way don't believe it is a real illness, that say it's all in your head or depression is the cause.
It usually takes people like us many years to be diagnosed, and like you said at that point dismissed from any long term help as it's chronic, uncurable, and mostly untreatable. however I do believe that Long coved has finally shone a light on these illnesses and worldwide their is going to be a lot of attention and research into this, and hopefully figure this out and how to help from a practical point of view, or some medicine that could come along one day. So there is hope. I know it doesn't help much in the meantime but please know you are heard, believed and understood, especially amongst similar suffers. Thankfully some people have amazing understanding and empathetic family, friends and Dr's. I hope you have someone in your life who is in this with you. For any doubters tell them to educate themselves if they care to understand. As for bad Dr's dismissing you or not helping you get your illness properly managed and improve your quality of life, be your own advocate and don't take no for an answer. Have a family member be there to speak up for you if you are too sick and weak to put up that kind of fight.
It would be helpful if you research the other above illnesses as I said there is so much similarities in symptoms, causes, treatment of the people from Dr's, and loved ones. And go on support groups online on specific health websites or Facebook groups where you can relate to others. I'm sure there will be some set for long coved sufferers by now, but the others I mentioned will still be helpful. Many have had these issues for decades and have great advice on how to pace your energy and activities in to bite size steps and plenty of rest in between, tips for pain, comforts, relaxation, meditation, mindfulness, vitamins, note books or post it notes or mobile alarms with reminders when forgetful, disability aids to help you around and help with every day care and mobility, and just generally have warm love and understanding from those who do 'get it'.
I wish and hope for you a good recovery. You may not ever get back fully if like ME and fibromyalgia, but have better days more and more if managed right. Yet again some people do make great recoveries too. So still never lose hope. Research, research, research as knowledge is power. Hugs xx