I've got ADHD (diagnosed as a child) and I kind of agree with you, OP.
I wouldn't necessarily say it's 'trendy', but it seems that the threshold has changed for want of a better phrase. Previously, it seemed to be something that would be investigated if an individual was struggling, but nowadays it seems that people who are doing OK in life will self diagnose after watching a tiktok video and then seek assessment.
I'm not talking about people that mask their symptoms and appear OK to outsiders (when inwardly it's often a different case). I'll give an example.
I read a thread a while ago on here by a middle aged senior exec who thought she had ADHD. She managed a team of 250 people and was earning into the six figures. She went on to say that she was well respected at work and her output was regarded as being industry leading.
I immediately thought I recognised the situation. She was going to say that inside she struggled tremendously and that it took all her energy to manage her job, leaving her depleted afterwards - how I always felt when I was a project manager.
Instead she said something along the lines of not every person with ADHD struggles and she'd never herself experienced either anxiety or depression. Her reason for having ADHD was that she procrastinated about doing the housework on Saturdays and was always losing her keys, alongside a few other things like going 'all in' on new things she discovered.
People were telling her to get assessed but I couldn't help but wonder if her lack of motivation on a weekend might actually be more to do with her being a working mum with three kids and a big job.
It's not a game of top trumps and of course some people are affected more than others, but to get a diagnosis on the NHS you need to show 'significant impairment in two or more areas of life'. Where's the impairment if you're smashing it at your job/home life and you've never struggled mentally?
I'm trying to get back on Ritalin which I now realise I never should've stopped (I didn't realise for years that they prescribe it to adults nowadays). I need to be re-assessed and I've been waiting 18 months and counting now. I can't help but wonder how many people like that poster are ahead of me in the queue.
Not meaning to sound bitter but none of the people I knew with ADHD as a kid/teen would've likely been successfully running a team of 250 people alongside managing three kids before they realised they might have ADHD. I could barely get through my lessons despite being in the top 1-2% for intelligence according to several educational psychologists.