Talk to your ISP about getting a modem only, without a built-in router, then purchase a separate router of your own. All-in-one modem/router combos are generally kind of crap anyway, and one that your ISP can control directly is obviously a problem on top of that. I get why they’d do that: most users don’t know a damn thing about how to properly set up their network, and being able to change settings without walking the users through it would simplify things. Still crap, but I get why.
Even if you have to buy your own modem, definitely go for a modem-only device and a separate router. Personally I go the extra length of having a modem, a separate wired-only router, and a separate wireless access point for wifi. Combo devices have a habit of not managing memory well and needing to be reset more often.
That would be easy to challenge under the same reasoning as what’s in the article, not to mention various anti-trust laws and ones covering anti-competitive business practices.
Doesn’t mean it’s guaranteed to stop them, but it’s definitely not going to be as easy as them flipping a few switches and saying “watch ads on our browser with no addons or GTFO”.