Consider cgo-free version of sqlite
Since this is a bit more involved in sqlite than most other projects, this might very well not be an option, but have you considered/tested using https://pkg.go.dev/modernc.org/sqlite instead of the standard github.com/mattn/go-sqlite3?
It is reportedly a bit slower since it's transpiled from c to non-optimized go but it has worked for my use-cases well. And building is a breeze :) (I actually could not build marmot without using a docker image on NixOS).
Are there any other cgo dependencies that I'm missing?
I've considered pure Go implementation before. My main motivation is to stick with the upstream so that people can get the latest and greatest features. For the build I intend to provide prebuilt binaries for all operating systems and CPUs. I already have work item to have MacOS binary part of build, but if NixOS is anything different then we can add that to list.
Again I am open to contributions.