Desktop is on the roadmap, not in your hands yet. Native macOS and Windows builds are planned, and we would rather tell you that honestly than put up a download button that doesn't work.
Desktop matters for a specific kind of user: the shop that keeps a machine at the bench, the surveyor writing up a boat, the property manager working through a list of units. Those are long sessions with lots of photos and lots of history — a phone is the wrong shape for that work.
fixin Web runs in any desktop browser today and covers most of what you would want a desktop app for. It is the fastest path to fixin on a big screen while the native builds are in development.
If desktop is the thing standing between you and using fixin at work, the beta program is the best way to say so — that feedback is what decides build order.