That PrePoMax looks quite interesting! Shame I cant run it in Linux.
For editing the input files, I use VS Code with the abaqus plugin. It has much more features than SciTex. Open Source, quite recommended.
If you want to open really BIG input decks, use Gvim, it has already integrated abaqus syntax, including card folding, which is super handy to overview an input deck.
Another very nice options is Sublime Text, my favorite text editor, but it is not free. Nonetheless its blazing fast and has also Abaqus syntax support.
CGX has a steep curve, but its incredible lightweight, which is important for very big models or when computer resources are limited.
My other option is to transform the FRD to Paraview with GitHub - calculix/ccx2paraview: CalculiX to Paraview converter (frd to vtk/vtu). Converts CalculiX FRD file to view and postprocess analysis results in Paraview. Generates Mises and Principal components for stress and strain tensors.
I do this when I need more detailed postprocessing images.