Is using the router and modem my cable company provided for my internet putting my privacy at risk? And if so, I have heard of openWRT routers but it seems like there’s quite a bit of a learning curve with that but even if I got one would I need a non cable company branded modem as well? Any specifically that anyone here would recommend?
For privacy, any ISP can technically see everything you do online including phone using wi-fi unless a device or syatem uses a VPN, Tor, or i2p, but that does not mean the ISP is keeping records of what an account does online. They may have no interest.
For security, you definitely need your own router. If you can build a system to use as a router running OpenBSD or pfSense, at leaat use a router with open source firmware so your router traffic is not going to someone else and an open source router will give you a lot more extensive network functionalities.
Not really correct. The ISP can see which sites you are visiting but thanks to https not what you are doing on it.
Just use OpenWRT. It supports about 1600 devices and is secure by default (low attack surface due to minimal design and hardened kernel)