Supposedly CableCARD is supposed to do the magic to let you see encrypted channels, but there are noises that some outfits are encrypting everything now.

https://www.google.com/search?q=mythtv+encrypted+channels

I signed up for YouTubeTV when it was $35 a month. (It's $40 now.) Still haven't used it, but they keep adding more channels all the time. We have AcornTV for the British murder mysteries, etc., also too. (And Prime, but we've never streamed anything from Amazon either.)

I'd be surprised if MythTV were worth the hassle, unless you have a lot of free time, love a challenge, and love to tinker. The cable companies are going to force us all to cut the cord, but they don't care because they're busy becoming WiFi vendors, movie and TV studios, phone companies, etc., etc. They think they'll get our money one way or another...

Good luck!

Cheers,
Scott.