Using our get-iso
tool - you can get the latest unstable preview
get-iso plasma --full --preview
Tool available with manjaro-get-iso package.
For as long as you are using Nvidia GPU there is no guarantee.
When you have a working system - disable update-nagging - create a snapshot of the stable branch packages and use it to install extra packages - what ever - this way you don’t get continued updates.
From your topic history it seems that Manjaro is not the right operating system for your use.
Perhaps Linux Mint or Ubuntu is a better match.