Fresh install

So i downloaded the parrot-gnome on my existing install and purged mate and it crashed my system after reaching out to a dev i understand that old and unmaintained so I chose to flash the new mate 4.7 and start over it runs amazing thank you for the hard work ,I’m just curious cuz I’m interested in gnome 3.34 what what would be my route to put it on my existing os I just don’t wanna break my fresh install

If you don’t want to have any problems then install from the repository I don’t know what version of gnome that is but if it is not that recent edition then you are simply out of luck. You could gather the necessary packages and dependencies yourself and install them or add in the needed source list entires but that clearly could cause problems with existing installed packages. Again no way to get around that.
For the record it isn’t the installation of two desktops that causes problems it’s that, what happens is you may not have all the necessary backend elements that’s why it helps to actually log in and check everything out first. Gnome-software does not and will not work properly and maybe some other elements.
Also another tip debian based distros won’t usually be first out or even very fast on updating packages by comparison to some other distro families because debian philosophy prizes stability over staying current.

Yea I tried that and had to purge it, it causes some sort of dependency issues and had to purge it and just lags really bad I’m just sticking with mate it runs amazing