You can put their modem in bridge mode and use it with your own router. That’s probably what I would do if I needed unlimited.
Since they're also using VoIP and cable from Comcast, I didn't go any further. I wanted to switch the DNS to AdGuard because my mother-in-law had a JavaScript pop-up that convinced her to call "Microsoft". I put uBlock Origin on Chrome and Edge.
Users can set the DNS setting on their devices to use something else but I bet it's a tiny fraction that do. As somebody who worked at an ISP, I can sympathize a little bit with not wanting customers to f*ck up their DNS.
>It’s $25 to use their modem and router
Honestly this is the biggest farce of the whole caps situation.
Forcing people to overpay to rent their crappy modems because it's $5/month LESS than using your own equipment which doesn't get benefits such as particular customer support or replacements. (If something is wrong with your service they'll likely blame your equipment)
Doesn't cost any more to turn off data metering on your own modem, it's just an incentive to kill the market of people having their own (often better) modems which otherwise would cost less in the long term.
I suspect it's just so they have a higher chance of padding their "xfinitywifi" network spamming more than anything.