c# uses nuget if you want, but easily integrates source and directly assembly "linking" if you want. Nuget uses the nuget API but easily accepts "sources" as feed urls. The API is public but not well defined, however they are plenty of feed hosting tools. I use Sleet and an http server to host mine. I did write my own search serve though.
little note for programing language fanatics
if your language has a centralised package repository
go fuck yourself
ie:
python
rust
javascript
if your language has a decentralised package management system, you are ok
c
c++
go
i don't even know how java imports work, i suspect they are decentralized, probably also C# and haskell and lisp and kotlin... again, no idea about any of these things, please do jump in and defend your language nostr:npub19mun7qwdyjf7qs3456u8kyxncjn5u2n7klpu4utgy68k4aenzj6synjnft
Discussion
The build system for C# (.NET anyway used synonymously but technically completely idependent) is MSBuild which doesn't care where the libraries come from as long as your project points to a place it can find and link them.
a lot of microsoft side projects were not terrible, and p2p was popular in amongst it all, maybe the only virtue of microsoft
C# at least was outside of Microsoft, and I think the Rosolyn C# compiler is still maintained outside Microsoft by the original developer. He may be on MS payroll, but I think its still independent. MISL and .NET on the otherhand, FOSS at least, but yeah captured by MS.