As an owner of two nVidia Shield Pro boxes (2017 pro & 2019 pro), I can say for sure, that these units, although expensive, Are definitely the way to go if you want to have an android TV box that will pretty much handle anything you throw at it. I have had several Chinese off brand TV boxes and none of them really did very well... I stream my media library from my NAS to both units in the house with no codec issues or lag/stutter at all, stream live TV via Sling TV, Netflix, CBS all access, and Disney+, play android games butter smooth, and occasionally play a game using Geforce now or Gamestream.. As for replacing your cable company, Youtube TV, Sling TV, Hulu, as well as several others, Are great options for cable TV replacement, they cost far less than cable (especially comcast) but you may not get every channel you had with the cable company. I would suggest shopping around with the different IPTV providers/streaming services before you commit. I have sling TV, and though I do not have the premium channels like HBO, showtime, etc. etc., I do have a decent amount of channels including a good amount of my local channels (the major networks) for right around $40 USD per month.. They have two base packages to choose from, or you can get both together (so technically 3 options), plus several ala carte options for adding additional channels on top of what ever base package you go with. The ONLY thing you need to consider beyond this, is whether or not you have a data cap with you ISP, as streaming, especially with multiple devices, CAN eat into that data cap every month, and if you are sheltering in place, could exceed your limits which in turn, obviously, would raise your bill with your ISP.
As with most things, getting started and buying the gear is usually the most expensive bit, but can in the long run save you a few bucks down the line.
I hope this give you some food for thought.