Freecad 1.0.2 is drafted in freecad: 1.0.1 -> 1.0.2 by LordGrimmauld · Pull Request #431206 · NixOS/nixpkgs · GitHub.
The file opening issue has been fixed in freecad: apply patch fixing crash on wayland by NickCao · Pull Request #434105 · NixOS/nixpkgs · GitHub, in the meantime COIN_EGL=1 freecad should work (or forcing x11 via QT_QPA_PLATFORM=xcb freecad)