I've been unable to play since the new version was released and would like to play again, but cannot free enough space on my laptop for the 50gb install. I tried using "manage installation" to select classic, but the installation size is the same and fails. Any help would be most appreciated, thanks!

Just get free space, do some cleanup, use cloud storage services, other drivers... 50GB is the standard size for a game these days.

Or buy the standard edition without the DLCs then.

Classic user support. "Just get free space".

Try the "Extras" part in Witcher 3 and download "Witcher 3 Classic GOTY"
That is v1.31 and consists of 10 parts, total 34GB.

Only downside is that you need to then install it from those files.
(Which is basically what GOG Galaxy does anyway... RIP... )

More better installers, like GuildWars 2 have the installer, launcher and game be the same file, and it will just stream down all the files it needs to a minimum of files in the subfolder and lets you even play the game before all the files are down.
(from 2014...)

That wouldn't be an offline backup installer if the installer is streaming the files from the internet as part of the install process - so doesn't meet the DRM free test.

Best advice for you if you can't free up sufficient space would be to download the installers, copy them to an external (USB) hard disk or NAS and install from there.

Assuming you are running Windows 10 or 11, there is a utilty in Settings>System>Storage
That can potentially clear anywere from a few hundred MBs to several GBs of space.
If you have a few dollars to invest, the 1 TB SSD drives are less than $50 now. If your laptop is old enough to still have a spinning drive in it, an SSD replacement would breath new life and performance into it.
Feel free to message me for more info or even technical details. In this last year or so, I have replaced around 50+ mechanical drives with SSDs, without losing data.