> Half of the time, PPAs don't work
I don't believe this, and I suspect you're doing something unorthodox with your apt sources (it wouldn't be the first time I hear a story like this).
PPAs build from source on a vanilla platform for the given configuration, so they're guaranteed to have standard output (binaries etc.) and dependencies. When there is a problem with a certain configuration, such build won't be available to the user.
Can you list the PPAs that don't work?
Half of the time, PPAs don't work. Snaps and Flatpaks are a step forward, but they still require a central server for fetching dependencies.
AppImages are good.