Hi there, thanks for much for the kind words!
I've just downloaded the tools from this page and loaded up the demo in Unity 2019 and failed to encounter any compile errors. The video is admittedly out of date since I've made some quality of life upgrades since it was published but the genral principles are still the same.
What errors are you encountering exactly? I'd hazard a guess it'll be something related to a newer version of Unity I've haven't tried.