I work in the field and am constantly shocked at the number of otherwise skilled practitioners that have a huge blind spots for autism, especially mild or low support need individuals.
The thing about masking is that it can also hide “impairment” so a good diagnostician should ask about the ways you might mask and the physical and emotional costs of the masking. Sure you can socialize with the best of them, but are you a hollowed out shell at the end of the day? Does the masking leave you with zero resources for your hobbies, less capacity to deal with stress, and burnout? High maskers tend to have higher burnout because they are working hard to function in a world that expects them to appear counter to their nature. All too often someone can appear to function typically but a few times a month or a year they have epic drops in functioning and can’t get out of bed or leave their dark room. They’re diagnosed with depression, which admittedly can be exacerbated by burnout. However, treating burnout with depression coping skills might miss the mark. Anyway, this is a huge frustration for me professionally and I’m sorry you are dealing with it.
I’m not in Europe so I don’t have a whole lot of knowledge about the healthcare system or how to direct you unfortunately. In terms of books I like Devon Price’s Unmasking Autism (one of the best for describing the experience of adults on the spectrum) and for younger AFAB folks I like Spectrum Girls Survival guide. I have skimmed and liked Field Guide to Earthlings but haven’t read it completely.
Also it’s a small organization but Autism Learning Lab is building some nice resources and education. I still believe a full formal social developmental assessment is helpful, but it’s expensive and if you don’t find the right practitioner they can still miss the boat. I tend to advise people to ask a lot of questions about their clinician’s expertise and experience with autism. Learning subtle signs beforehand and asking if they are aware of the “pink flags” etc. described here could help.
https://pubmed.ncbi.nlm.nih.gov/34121610/