I don’t mind the package manager differences. What i have started to find annoying is different languages or sites requiring their own installers. Like pip or npm or git etc.
I’ve only ever used debian/ubuntu linux versions and there is some differences, but between dpkg and aptitude/apt-get/apt, it isn’t too much to deal with.
And some package manager have been designed ground up to work better with a certain build.
I hear arches manager is super fast. But i’m good with apt.