If your intent is to have your code reach the maximum amount of people to benefit them, and you want your project to benefit from networks effects.. then GitHub and Discord, the two proprietary platforms used by the largest portion of people for modern OSS project development, are basically a non-choice. Every other option results in far less people discovering and interacting with your project, by orders of magnitude.
In a project I run, we forced everyone into Matrix as much as possible and refused to operate a Discord for over a year. Once we relented, and decided 'we would run both' - over 95% of people in under a month stopped participating in the Matrix channels and instead went to Discord. The number of people in the community grew orders of magnitude larger, in a shorter time period, as well - even with us pushing it less on our docs/etc.
It sucks. Wish it wasn't true - but that's where people are.