It seems a common issue, but I have no TV provider. I cut the cable and got a Roku. I refuse to buy a Disney channel or some omnibus channels with dozens of things I'll never watch. I just want to watch a sports event on CBS, and it's there, but Roku keeps asking for a TV provider.
I think you'll find that it is CBS that wants a TV provider. They want to make sure you're paying for their content via some means. Possibly Paramount+ would be an option for you since that includes your local CBS channel (depending on what level of package you sign up for.)
All of the TV Everywhere apps require some form of Live TV service (cable, satellite, streaming).
As noted for CBS, it depends on what you want to watch. For live sports, you don't have many cheap options. You can get the higher-end Paramount+ with Showtime (ad-free), which gives you a live feed of your local CBS station. But that live feed is just that, live only. No DVR or rewind or anything similar. If possible you can get an antenna and watch for free with your TV. You can also get one of many external tuners that usually have DVR features, too.
Otherwise, it looks like CBS is typically only available with full cable-replacement style services, with their high prices.
Or you can give up on sports, and then just use regular streaming services for "next day".
