Did ATT specifically say that their modem will factory resets due to loss of power? Because that's genuinely unbelievable as a design feature for domestic-grade equipment. More reasonable would be that the modem will reboot when it encounters a brown-out condition, where the AC voltage briefly dips too low for the circuitry to continue operating.
A power strip with just an MOV circuit would only help if the problem was a brief spike in voltage. A power conditioner would only help if it's the shape of the AC voltage that needs to be cleaned up. That is to say, no dips or spikes, but rather the sinusoidal shape is messy due to other devices in the building.
A UPS (which almost always includes an MOV circuit and power conditioner) would switch to battery power whenever there's a problem with the AC voltage, so any momentary issues will be addressed. This switchover tends to happen within 2 cycles of the 60 Hz AC frequency, and that's generally good enough most home appliances. I'm guessing the modem has a switch-mode power supply, so even a cheap UPS with square/stepped wave output will work.



Having spent much of my software engineering career training and mentoring interns, new-hires, and transfers from other departments, and having toiled with some of their truly inexplicable questions that reveal shaky technical foundations, I can understand why so-called AI would be appealing: inexhaustible, while commanding the full battery of information stores that I could throw at it.
And yet, the reason I don't use AI is precisely because those very interns, new-hires, and transfers invariably become first-class engineers that I have no problem referring to as my equals. It is my observation that I've become better at training these folks up with every passing year, and that means that if I were to instead spend my time using AI, I would lose out on even more talented soon-to-be colleagues.
I have only so much time of my mortal coil remaining, and if the dichotomy is between utilizing inordinate energy, memory, and compute for AI, or sharing my knowledge and skills to even just 2 people per year for the rest of my career, I'll happily choose the latter. In both circumstances, I will never own the product of their labor, and I don't really care to. What matters to me is that value is being created, and I know there is value in bringing up new software engineers into this field. Whereas the value of AI pales in comparison, if it's even a positive value at all.
If nothing else, the advent of AI has caused me to redouble my efforts, to level-up more engineers to the best of my ability. It is a human legacy that I can contribute to, and I intend to.