most of the useful stuff? can you point me to some data that shows which "useful stuff" is lacking in sid?
what is the actual issue? inability to compile things from source or not knowing that you can install to /usr/local/bin or $HOME/bin etc?
of course everything is either on gihub or gitlab in 2020. the argument that the majority of software that is useful isn't actually available as deb package is false. useful to who? based on what arguments?
To clarify your edit, I am mostly concerned that I want to pull in another deb repo or something so when I do an apt update I get a full set of updates, not the distribution packages and a manual compile job to argue with.
I have been running Debian sid for many years for various scenarios and not once had an issue with stability or that I got bitten by a bug.
In production I want stable at all costs. For anything in between building from source is always an OK compromise.
The premise that Debian sid has poor quality packages is a blanket statement that is wrong.