There are pretty good Remote Job sources these days, try them. There are quite a bit of contract works too, which you can start off with. Also, do not forget to walk into your area's agencies, they usually work with freelancers/contractors.
We're working on and will keep improving the app. Try being a bit more specific with your search keywords, permute-combine keywords, use the "Setting" for a more granular control of what shows up.
Anyway, that same "linux" posts also has "UX" and that might be the reason for your result.
Do you remember which post was the one that you got the wrong one?
- https://www.workingnomads.co/jobs
- https://remoteworkhub.com/remote-jobs/
- https://www.crossover.com/
- https://remote.com/
- https://weworkremotely.com/
- https://getbetterluck.com/ (one of our own internal tool)