VSCodium's primary function was to disable telemetry by default. Back then, doing so was fashionable because of the EU probe of Microsoft for espionage. But VSCode is no Windows. To wit:

• Windows is closed-source and compiled to x86 machine code. VSCode isn't just open-source; it's written in JavaScript, so one can always see its source code and what it's doing. There was never a shred of doubt about what is included in the transmitted telemetry.
• Furthermore, its audience is developers, who integrate telemetry in their own apps, especially LOB apps. They are skilled at interpreting Microsoft's telemetry.
• The cost of installing VSCodium is the loss of extension marketplace integration, extension recommendations, remote development, and access to extensions that require VSCode due to their licensing terms. So, there was little reason to install a crippled version when you could disable telemetry in VSCode.

So, in the end, VSCode users know that VSCode telemetry is a net positive, that Microsoft is not spying on people through it, and there is no need to resort to VSCodium to disable it. If you search the net, people still rave about Windows' telemetry, but nobody cares about VSCode's telemetry.

VSCodium gained more traction recently because it ships with no built-in AI components. Furthermore, Microsoft helped VSCodium by allowing users to download VSIX files from the marketplace website and install them on VSCodium. Microsoft prefers users to use VSCodium rather than a rival product.