If you don't have a 4k monitor, the 4k resolution is wasted

This is usually incorrect in practice since 1080p uploads rarely have enough bitrate to match a 1080p monitor. Resolution is not that important, but bitrate is

That's what happens when you don't have parity and backups. It'll happen to your optical media too, just give it a few years

Try wrapping your phone in aluminum foil and running a speed test. You'll find that modern radios have plenty of SNR to spare