I needed to install VMWare Horizon client on my Slackware system at the start of COVID lockdown for working from home.
I did look at a
Slackbuild but ended up just downloading the Linux tarball version and playing with that until I got it working.
The Slackbuild was out of date then and has never been updated. There is a vmware-bundle.eclass file that is used by the Slackbuild for extracting components from the bundle that might help.
I did not have to deal with any Python issues back then. Times may well have moved on. I certainly have as I do not need VMWare Horizon client any longer.
Persistence will repay. Good luck.