I'm sorry you have to deal with this stuff. Here are some thoughts and experiences:
For cell phone service, search the web for info on 'MVNO' - MVNOs lease bandwidth from the big guys and resell it to users like us. Search for a list of MVNOs, and I expect you'll see some familiar names. You might get a better deal from unfamiliar names, though.
We use cell data like you do and a(n) MVNO; if we use cell data, we pay by the megabyte, but we use very little cell data. Our monthly bill is usually $27 for 2 smart phones.
I found the one I use because an SI member asked for feedback in Off Topic. IOW, if you do some research and ask questions, you're likely to get good info.
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The Big 3 seem willing to sell Internet access without cable TV and phone service. Around here Comcast charges $52/month for 50 or 75 mbps, and ATT charges a bit more. A new cable company is wiring my city, and they charge $30 for 300 mbps service. Check with your providers for their charges for Internet-only service.
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For TV, I went to streaming and dropped cable a few years ago - Sling, Netflix, Amazon Prime, and some other services for limited periods. The prices keep going up but remain cheaper than cable for equivalent service.
There are some free streaming services that have immense libraries - Tubi, Pluto, Crackle, Freevee, Filmrise, Plex ... each one overwhelms me with choices. In fact, there are so many choices that I often can't choose and just go back to .Perry Mason' and 'Matlock'.
To use all these services, I bought a Roku, which I upgrade every 3 or 4 years. Every so often I look for cheaper alternatives, but I haven't found any.
HBO now broadcasts via the Max streaming service for $10/month and up, so you can give up cable and still get HBO.
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My reco is to do some research, if you have the time and energy, and figure out how to get what you want. Figure out the cost. Then call your cable company and tell them you want to cancel. They'll probably give you a deal that's at least close to building your own package.