

Maybe check your local Craigslist or e-waste recycler? Someone on Craigslist near-ish me has a 10" Dell Inspiron laptop for $25. There’s also a HP mini 110 that the seller is asking way too much for, lol.
That size of laptop/netbook has kind of fallen out of fashion and it seems to be touchscreen tablet-likes in that size now. You’ll want to keep build quality in mind with the older machines because a lot of stuff is soldered together at that size and age, I had a HP Stream 11 and the hardware recently failed - it was e-waste when I bought it but it ran Linux well until it died.
Timberborn is awesome. I play on the stable release (non-experimental branch) through Proton experimental and it runs about as well as it did under Windows. I’m running Bazzite (Fedora) though so my system is much more up to date than Debian, but I bet one of the awesome nerds here could help you get it running on Debian.
Proton DB page for the people smarter than I am, lol