There are dongles that take HDMI input and plug into a USB port for output, and they are extremely cheap. They are readily available online for US$10-20. I've had one that looks like this for several years:

Until today, I'd never plugged it in. It was probably pretty cheap and I bought it for hazy future use after seeing it mentioned in some article somewhere. The future is now! The documentation that came with it claims it can accept an input of 4K@30fps and output FHD@30fps. I don't know if that claim is actually true. Even if it is, 30fps is less than desirable for watching TV. Newer iterations of similar dongles claim to output up to FHD@60fps. My TV is only FHD, not 4K, so FHD@60fps would be fine for now if it turns out to be true.