You're not going to get a different answer here to the comments David and I have already left on bugzilla.
I don't understand what you think the problem is. >...But both modules can't be loaded at once. Not technically true, but they would interfere with each other. But in any case plasma-pa disables device-manager when we enable switch on connect. >So plasma-pa's "Automatically switch all running streams when a new output becomes available" checkbox does not work in many circumstances. That's not what any of your links are about, also it doesn't make sense as described because we disable device-manager when we enable switch-on-connect. See ModuleManager::setSwitchOnConnect. David
