For 16 GB SSD with 4 GBs of RAM (which is what most Chromebooks used to be), you will need Debian with XFce, with 2 GB of swap partition. Nothing else will either fit, or work properly. I have given away 3 such laptops to friends with that setup (Arch might fit ok too, but because I was giving it to friends, Debian was easier to work with). After installing the v12 Bookworm Debian OS, with libreoffice, a couple of simple games (e.g. solitaire), Gimp, and that 2 gb swap partition, I was left with 5 GB free space. I had to occasionally do sudo apt autoremove to make sure the space wasn’t eaten away, but overall, it stayed steady (dh -h will give you that info). With Trixie, you might end up with 4 GBs of free space, as it’s bigger. Bookworm has updates until 2029.



You will have to reinstall the OS, and redo the partition table (256 MB boot partition (that’s enough for a single OS), 2 GB swap, and the rest / root partition). Then install Debian with XFce on the / partition. You use it normally as with any other Debian-based OS, that Zorin is also one of them, but you use the terminal to update the system. It’s very usable.