Multiple subjects being addressed here.
1) Wireless service -- AT&T, Verizon and T-Mobile are pretty comparable nationwide but in a given neighborhood one can have the edge over the others based on the location of towers and other factors. Tower locations are on maps that are publicly available and that can help you figure out what is the best service for you. (and a lot of times they share towers so the service is going to be similar across brands). Tip for people in areas with good Verizon service -- Total Wireless sells unlimited Verizon network wireless for a flat $25 a month and it's just as solid as Verizon service that costs 2 to 4x as much. Total is actually a Verizon subsidary. I recently upgraded to Total's 5G ultra-wide-band tier at $35 a month but I haven't been in a situation where it was worth the extra 10 bucks, so I will go back.
2) Internet service. If you have FIOS available to you (most of the country does not) it will probably be the best deal and it is extremely reliable. Where we are there's only been one FIOS outage in three years. And we pay $43 a month for 300 megabit service (I can't imagine any normal household needing more bandwidth than that).
3) Home wifi -- relies on your router but your computer is often the culprit. It is worth buying updated routers/mesh every 3 years or so because protocols change and you will have less problems running, say, Wifi 6, than previous wifi iterations. When I have wifi problems it is almost always on my Windows computer and it is almost always because of Windows 11 quirks and bugs. Example: Windows 11 has energy saving logic and can switch off your laptop's wifi chip, but the problem is when it turns it back on, there are bugs and Windows gets confused about the location of the DNS server so you get "can't find the internet" -- this is totally Windows' fault and the only fix is to disable the energy-saving logic (which doesn't save any appreciable amount of energy, it's just dumb).
Basically if you are having wifi problems, always test with your phone first. If your phone has internet and your computer doesn't, it's probably not the fault of the router, it is probably a Windows thing (and newer Windows causes more problems than older Windows).