Patrick,
In ClearOS/Centos there is no package called libpython3 to my knowledge, instead I think you mean python3-libs...
Anyway, I will likely update my instruction above to do in the build machine before doing the rpmbuild -bs domoticz.spec command. I am not sure if it is needed, but it will at least take care of an error message. Also, I will try to update the spec-file itself to make sure python 3.6 is installed together with domoticz.

Expect a domoticz-2022.1-3 update in a day or so.

/Fred