Sometimes, and it's not been tracked down exactly, some dependencies of the site aren't built even though it says they are. In those cases, re-run pnpm bootstrap and pnpm build to re-build all the internal site deps.
The Windows support for watchman is a bit meh. It's not likely to get better, given how well WSL works now. So, you could use WSL to work around that.
Though, for a lot of changes to the site: Watchman is optional. All the watchman script does is run pnpm run --filter=[xxyy] build when you save in a package which is not typescriptlang-org (the gatsby website).
To run the site without watchman, use pnpm run --filter=typescriptlang-org start.