Eli5: your PC has different access levels a program can run at. This prevents a malicious or badly coded program from completely fucking your computer. Kernel level anti cheat runs at the lowest level access that exists under windows. It can do basically whatever it wants to your PC, and if a backdoor is coded in (happens way more than you’d think), it gives malware basically total access to your PC.
I think it depends on your use case and how strapped you are. Unless you’re gaming, you don’t need a super performant phone these days. Anything midrange will perform around the same as a flagship in normal phone tasks. What does matter is the form factor, battery life, and support window.
That being said, I basically only recommend the pixel series these days, because they support grapheneOS and they’re just cheaper than other phones with that long of a support window.
Samsung and Motorola do make some nice hardware though.