> I want all of the QT libs embedded in the package.
I don't understand why anybody wants this.
Libraries should have major versions and the latest of each major version should be compatible with anything using that major version, because that's what major version means for a library. You might then need to have more than one major version of the library installed, but any two applications using the same one should be able to use the same copy, and then have it maintained by one person in one place.
If every package has a separate copy of every library, people have to maintain them all separately. When that library has a security update, you now have to update five dozen packages instead of one or two, and have a security vulnerability if any of the maintainers don't keep up in a timely fashion. Which not all of them will.
> I want the proprietary app in a container.
People want containers to be magic but they're actually a hard problem. You want the app not to be able to do anything you don't want it to but still be able to do everything you do want it to.
A backup app that can't read my files is useless; it can't back them up. But it shouldn't be able to modify or delete them. But it should be able to modify its own state. It shouldn't have general network access but should be able to communicate with the backup server, which might have to be specified by the user and not the package maintainer. It doesn't need access to the GPU or the ability to use gigabytes of memory, but it does need to be able to transfer a lot of data over the network, but the data it transfers is lower priority than other network packets.
That requires the person configuring the app's container to have both detailed knowledge of the app and detailed knowledge of the container system. It's common for this not to be the case.
And that's why containers are a mess, not anything to do with the package manager, which should have little to do with the container system outside of packaging the app's default container configuration with the app.