As a hobbyist, I just email the author, thank them for their work, maybe ask a question about or comment on their work and ask if they have the specific paper I can't get. Nobody's ever said no and I've asked dozens if times in CS, linguistics and for some climate and geography stuff. Academics are pretty accessible and even willing to chat about their work as long as you're not a crank.
I was super surprised the first time I emailed a researcher and asked them a question about their work while mentioning I didn't have access to their paper. A week later an envelope arrived at my office with the paper in it. This was last millennium.
This works in almost any field. Researchers generally love to hear from people, will usually answer whatever questions you might have about their work, and will happily give you a copy for free
