Local channels can be obtained through an antenna, if you have the ability to get good reception. Otherwise, you can look and see if Locast is available in your area. It provides local channels for about $5/month, but isn't available everywhere. YTTV will give you local channels, but if you need the RSN's you're out of luck as someone stated above. Hulu has the RSN's for now, but many seem to believe that's only temporary until their contract with Sinclair runs out, and then they'll be in the same boat as all the other services that have had to drop the RSN's.
We weaned ourselves off sports (that's been one benefit to the pandemic, anyway) this year and now only use Netflix, Prime, Disney and Frndly TV (mostly for Hallmark). So now our TV bill is super cheap. Sports will keep you tied to cable or a similar service, and even the YTTV's of the world are raising prices to where it's getting close to cable, especially when you factor in you'll still have to pay for internet if you had bundled service with your cable provider. We do get ESPN+ through the Hulu/Disney bundle and that provides enough lower league sports to satisfy any urges. But you won't be able to see major teams on there.
Sorry I can't tell you anything about ATT, but I refuse to touch anything they offer with a 10 foot pole. Bad past experiences. Very bad.