Same here. 22 years experience full stack; leadership roles. Can't get an interview. Taking an ML class. I think telling some recruiters I had a baby on the way was a mistake.
I don't even know what the overlap between people that are looking for jobs at my level and people who have managed huge teams is... everyone I know who have managed teams that large is on massive comp packages at FAANG type companies.
It's all very confusing, it made me feel like I've picked the wrong field. I have been lucky enough in my career that I have a long runway, but I'm also not rich enough to retire and do something crazy like buy a farm like I've seen other people in my situation do.
Very frustrating situation, I have been trying to work on my own projects but I'm not a natural salesperson so it takes a lot of effort to motivate myself to do things like cold calls or even cold emails.
I am a contractor and for the most part it's still, thankfully, a meritocracy. So experience is, in my opinion, the biggest factor.
I have no doubt that sometimes, perhaps for the entry-level roles, they will discriminate against age but for senior roles, due to the cost of the candidate and the potential damage they can do, a younger candidate without the experience, could affect them badly.
As a full stack developer, you were expected to be able to do system administration for Linux, setup and configure Apache httpd server, work with MySQL (create tables, know SQL), and work in a language that typically started with 'P'. The way that CGIs (and Php) worked implied that you did front end and backend work as necessary... though front end didn't have the same degree of complexity that it does now.
Full-stack adds the front-end, and that's why you won't find js devs that can configure nginx, because they've been surfing on that "full" part of "full-stack" for years but it really just means you can do node and JS.
Writing the page to do front end navigation was part of the expectations of the fulls tack developer. They may not be a web designer, but the "ok, this is what the designer wants the page to look like - here's the HTML that I need to write to realize this" was part of writing the perl (in my case) CGI to make it spit out the proper html in the proper spot... and you really can't do most php without doing front end development as an integral part of it.
The definition of full stack has changed over the years as the stacks have changed and more emphasis is on the front end as front end libraries and frameworks have evolved to take more of the heavy lifting for presentation.
I think the best description is "give me a piece of tech and I can probably figure it out"
Best decision I ever made.