I analyzed the two packages and I think I found the reason why they break each other: both contain /usr/bin/chardet and /usr/bin/chardetect (as well as the associated man pages).
So, a possible solution could be remove those two binaries, and their man pages from both python-chardet and python3-chardet, and create a new package "chardet" on which both would depend.
Of course, this is just a suggestion, and I'm pretty sure the package maintainer is well aware of the situation and has his own reasons not to split the packages.
I analyzed the two packages and I think I found the reason why they break each other: both contain /usr/bin/chardet and /usr/bin/chardetect (as well as the associated man pages).
So, a possible solution could be remove those two binaries, and their man pages from both python-chardet and python3-chardet, and create a new package "chardet" on which both would depend.
Of course, this is just a suggestion, and I'm pretty sure the package maintainer is well aware of the situation and has his own reasons not to split the packages.