Please do not tell people to remove their package management software. I’m assuming you made a mistake in good faith but telling people to damage their systems is not ethical.
My question was not answered because it asked for two things and you only provided an answer for one of them. You replied with how to remove software but in a way that prevents updates and the question was to do both remove the software with memory leaks and still get updates.
You asked me to open a bug report but it would be a duplicate of the existing bug report. If you examine that bug report it was closed and reopened in the past rather than opening a duplicate.
Instead of uninstalling stuff, you can disable the automatic updates in the GNOME software center. That should be enough to prevent the memory-leaking service from starting until the bug is fixed.
Regarding updates, you can still keep your system updated through dnf instead of packagekit. Use sudo dnf upgrade to perform a system update, and if you’d like for this to be done automatically, take a look at dnf-automatic.
I can’t speak for the packagekitd memory leak but on my old dual core 4GB ram machine, the gnome-software + packagekitd combo was taking too much CPU power during boot and not to mention about 900 mb of memory.
If you are comfortable with the console and dnf, I recommend disabling gnome software from running on autostart. This in turns prevents packagekitd from loading upon boot as well.
Instructions on how to do this are nicely layed out in this reddit post