Steam Link on old hardware won't probably go well.

Game streaming benefits greatly from hardware video decoding — to the point where it's practically required for smooth streaming.

Mac Mini's CPU and iGPU might support that to some extent, but you'd be most likely limited to H.264 and 1080p — no newer codecs and no 4K.

You don't need exactly Google's Chrome though. ungoogled-chromium works as well and it doesn't send a bit to any of Big Tech's servers.

I have it installed and I have already bookmarked 10+ different flashers and updaters I've needed so far. And I genuinely think it's better than 10+ poorly made Electron apps I'd have to install instead.

Though I wouldn't daily drive a browser that allows websites to screw my USB devices.