It's absolutely irresponsible of Google to continue to promote Chromium-only APIs such as the File System Access API as if they were standard APIs you can use with the expectation that cross-browser support will come eventually
Glossing over the difference between APIs that have genuine cross-browser implementation interest and Chrome-only APIs that are unlikely to ever get implemented in Firefox or Safari is tantamount to tricking devs into making their projects Chrome-only.
Just be really REALLY careful when you read anything from web.dev or a domain with Chrome or Google in the name about exciting new standard web APIs. Much too often what they are promoting is effectively a proprietary API that other browser vendors have serious concerns about.