TubeDL saves YouTube videos up to 8K AV1 with the original audio, as MKV or MP4, straight to your disk.
A small browser helper (Chrome, Brave, Edge) does the work on your own connection — nothing goes through a server, so no bot-checks and your speed is your line's. Age-restricted videos work if you're signed in to YouTube.
Free seat: 5 downloads, 2 GB, no expiry. First 100, then a waitlist. One-click helper install and a native Mac app are next.