After running update indeed stuff started to 'work', but almost everything (like cmake) refuses to install because the rest is too old (it complains), so I ran upgrade. I guess I shouldn't have done that as it doesn't work

It segfaults (this has been discussed here already) and after it Networkmanager is dead (libnl.so.1 has been replaced by libnl.so.2). I cannot compile Networkmanager either as it has needs a recent version of intltool
But cmake was installed after the upgrade but that's also an ancient version ; nothing recent works without it complaining cmake is too old.
So how do I get a recent cmake working without killing Networkmanager? And can I get Networkmanager back again without reflashing?
(Note that cmake doesn't want to compile from scratch; there are 100s of errors when attempting that)