Meh, I've had same provider for years, now Spectrum owned and never had them blame my modem. I've owned my own for over 20 years, I mean they were replaced a few times to keep up with newer standards and higher speeds, but never a problem.
What the techs have always wanted to do instead was replace the cabling. Once, on an underground stretch from the street junction box to my residence outside box, that was really needed. The rest of the time, the techs were clueless as the signal strength was not low, nor intermittent.
IIRC, with a new account, Spectrum throws in a modem for a year or two but then starts charging a monthly rental on it. I'd just pick up any Docsis 3 or better 3.1 that has at least 16 channels, or better 32 or more in case they give you a free upgrade over 100Mb or at some point you decide you want more. Spectrum should have a list of compatible modems on their website.
Wifi router, much larger topic. Depends on the standards the clients support, range needed, # of clients, budget, etc. Get at least an AC model if not AX, and you are better off getting one with a USB port even if you never intend to use it because that typically means it comes with a higher capacity, longer lasting power brick.
I assume you wanted makes and models but there are several to choose from. Offhand, one of the most supported modem brands ,and decent quality is Motorola, something like an MB7621. Router, as already stated there are just too many to pick one, but Asus usually makes good routers and at a similar $75 price point, maybe something like their AX1800 model.
Routers, it's really a tough topic, I mean I have had flawless service from many models that some people swear are problematic, but on the hand I only use routers that I can flash DD-WRT to, and run that. I've had to repair a few due to burst capacitors so ideally you'd get one that does not have any internal electrolytic caps. If you don't know, you can look up internal pics on FCC's website.