Theoretical, you said? Theoretically no-one listens to FM radio or uses a computer for delaying TV broadcasts. For listening to the radio, most broadcasters are in the Internet. If you need a TV tuner for your computer, choose a monitor including one, or even use a TV for a monitor. If you need to "record" a program, get a cloud based service for that, or maybe the smart TV has the ability to save chosen programs on an external hard drive.
And yes, I'm serious. There was a time when building a Linux based home entertainment computer for saving TV shows was both cost and space effective, but as your experience with discontinued cards shows, not any more. Everything is in the cloud. You won't need a card, you'd only need a browser add-on. Funny thing is, saving TV shows on a hard disk with a set-top box is fully acceptable whereas doing the same with a computer program can be considered as violating copyrights.