Your best bet is to get an SiliconDust HDHomeRun box. You can get the antenna version or the cable-card version for your cable TV.
This one even support 4K ATSC 3.0 TV over the air. So if you are in a major city they are probably already broadcasting in 4K. This is $200 and needs a network connection so you can put it anywhere in your house, Doesn't need to be close to your server.
https://www.silicondust.com/product/hdhomerun-flex-4k/
https://www.amazon.com/SiliconDust-HDHomeRun-Flex-ATSC-NextGen/dp/B092GCN9NL
This is the cable-card version where you get a cable-card from your cable company and then you have full access to your cable TV to pull it in to Jellyfin. This is $150.
https://www.silicondust.com/product/hdhomerun-prime/
https://www.amazon.com/SiliconDust-HDHomeRun-PRIME-Cable-3-Tuner/dp/B004HKIB6E/
The Steam Link is great, but if you have a few bucks to spare get yourself a Nvidia Shield TV. You'll be able to stream PC games, play Android games/apps, and you can add a HD Homerun Prime down the line to make it a cablebox/dvr.