If and when you Upgrade to a 4K screen and Better graphics card and Processor...
you can Always download the 3K version again,
or What I do, Is I download Both..
( since you already have some downloaded in 3k - don't waste the bandwith. Rename the Folders and save them for later )
I download in 3K, rename the models Folder to e0100-3K
then Download the 1080p version, it creates a new folder e0100
so then I have two folders e0100-3K and e0100
I have a 5TB external drive ( 2) actually, 1 is a backup copy of the other.
So I don't worry about the space for now.
All but One of my Computers need the 1080p version as the 3K content Stutters a bit on them.
My work computer is powerful enough to run the 3K cards on my 4K screen.
So there I use the 3K clips.
But at home, I can only run ( smoothly ) the 1080p clips.
PS: anytime I want to switch versions, I just rename my folders..
e0100 --> e0100-1080
e0100-3k --> e0100
Take a few seconds if I just want one or two cards...
but I also have a script that does them all automatically