The Windows .zip package is the portable version. It is independent of the stable .exe version.
Use the .exe to install the stable release, and associate the files to that version (Ctrl+P).
Make a separate folder (Beta Studio) anywhere you like and extract all the contents of the .zip to that folder, but do NOT associate .3mf, .stl, and .step files with the beta. When a new beta is released, just extract the new .zip contents into the same folder, overwriting the previous files. All of your presets will synch through the Bambu cloud to both stable and beta versions.
