I also fired up a 2006-era original MacBook fairly recently, running the first Intel version of macOS (I've always had a soft spot for Tiger, its version of Aqua is honestly one of Apple's prettiest interfaces in my mind), while it works with modern-ish WiFi all the certificates are long expired so few things actually connected. I'm not sure how bodge-able this problem is, I never had time to find a solution.

It's a shame, because I'd love to use Tiger as a distraction-free environment. I'd even try and build a controller app for Tidal or Spotify so I could still have modern music streaming facilities. I spend a lot of time SSH'd into servers anyway so the lack of modern compatibility doesn't matter as long as a terminal's available.