PyQt5 is released under the GPL v3 license and under a commercial license that allows for the development of proprietary applications.
GPL is a viral license, the point of viral licenses is to infect everything. If one uses any GPL lib from a program/lib, that lib/program is legally required to be under GPL or AGPL, unless the copyright holder has given you a permission.
That's why this lib is mostly unneeded: PySide2 is already under a permissive license, PyQt cannot be used at all in permissively-licensed tools, and supporting both versions of PySide has a very minor benefit.
Suggestion: drop PyQt support as soon as possible.
GPL is a viral license, the point of viral licenses is to infect everything. If one uses any GPL lib from a program/lib, that lib/program is legally required to be under GPL or AGPL, unless the copyright holder has given you a permission.
That's why this lib is mostly unneeded: PySide2 is already under a permissive license, PyQt cannot be used at all in permissively-licensed tools, and supporting both versions of PySide has a very minor benefit.
Suggestion: drop PyQt support as soon as possible.