Some games that I've played on my low spec laptop:
Tangledeep
The Bard's Tale Trilogy (remaster, though the originals may work via emulation)
The Quest (some actions do require mouse/trackpad usage, but the game is strictly turn-based, so that helps)
Note that my laptop's specs are worse than yours (except for RAM), and that I am running Linux on it.
Also, I've played Celeste (not on GOG, but DRM-free on itch.io) on my desktop (with broken cooling) without issue, so if you have the means to play a 2D platformer, you might check it out. (If you're worried about length, don't worry, as there's tons of extra challenging content, including a chapter that was added later that's by far the longest in the game, and there are custom levels out there if that's somehow not enough.)
mcphail: Any of the classic RPGs should run well. I'm currently hundreds of hours deep into Neverwinter Nights Enhanced Edition. The huge repository of community modules is, essentially, endless.
[...]
Morrowind doesn't need a beast of a machine. Again, hundreds of hours in there.
These two games, I believe, really do need a mouse, however. I would not suggest trying to play them with just a trackpad.
(I don't know about NWN, but I know that Morrowind also needs you to use the keyboard at the same time.)