about the TF:S2 https://github.com/github/dmca/blob/master/2024/01/2024-01-10-valve.md - apparently bundling and distributing their assets isn’t cool.

Makes sense then. If they doesn’t use Valve asset but only the IP, and don’t distribute outside of valve preferred method, then they won’t have any problem from Valve (see: Black Mesa). But it seems like they already have problem with the development and Valve is just the final straw.