I consider myself extremely lucky in that the clinical lead at my Long Covid clinic is also a specialist in ME/CFS. She has been absolutely adamant that I ignore the naysayers who insist my symptoms are just due to anxiety, and has probably prevented me from gaslighting myself at times when I started to even doubt myself.
But I know others with ME/CFS and/or Long Covid have not been so lucky. One thing I emphasized repeatedly during the consultations to create a Long Covid diagnostic/treatment tool is that medical professionals must have education about the condition, and patients must feel seen and heard. They have to genuinely feel that their symptoms are being recognized and taken seriously. That kind of disdain (due to your weight, due to your sex, due to anxiety, and so on) is why some people I know haven't even gone to their GP due to fear of not being taken seriously and damaging their relationship with their doctor.
There are anecdotal stories everywhere about people who were fobbed off by doctors (not necessarily in the UK, but in the US too) because it was presumed weight was the issue. And by the time the real issue was identified, some of the harm/damage was irreversible, or it was too late for treatment. Or heck, even more basic than that, it was more unnecessary time the person had to suffer. Tragic.