If I try to start my unregistered Python 3.9.18 in PyScripter 4.3.4.0 (both 64bit) PyScripter seems to do nothing. I'm using the "Setup Python Version" dialog, but after activation nothing happens.

Update Slicer's Python from 3.9 to 3.10. Based on Slicer's previous update to Python 3.9 at 64.7% readiness and Python 3.10 at a higher readiness than that, this means Slicer can consider Python 3.10 ...