System command '"/usr/bin/env python" ./.wait ...' failed when calibrating through DaVinci Resolve

[filmmakerto]

First of all, thanks a lot for keeping this great tool alive.

I've got an issue trying to generate a 3D LUT for DaVinci Resolve on Arch Linux. The goal is to use this LUT in Resolve to calibrate a display that is connected via a DeckLink video card.

If I select the display itself in the "Display" dropdown in the "Display & Instrument" tab of the UI, everything works as expected. However, if I select "Resolve" and connect to the monitor calibration feature of DaVinci Resolve Studio 18.1.2, the color patches on screen are never updated and I get the following command line output repeatedly:

sh: line 1: /usr/bin/env python: No such file or directory

dispread: Warning - System command '"/usr/bin/env python" ./.wait 0 0 0 0.000000 0.000000 0.000000' failed with 32512

This is true no matter if I select "Light Illusion" or "Calman" as the calibration tool in Resolve, and no matter if I install DisplayCAL from source as described in this repo's README.md, or from the displaycal package in the Arch community repo.