

Problem is that distro1 has req-lib2.5.3 while distro2 has req-lib2.7.8, but your project was developed on distro3 with req-lib2.9.5 so you have to deal with every distro having different lib versions and compatibility issues that come with it, not just different packaging formats.
And since Arch is rolling release it’s python-lib, not python3-lib. :)