Well it is possible to just disable both of those, but I guess from what you say your motivation is to make it so you can't just re-enable them (though removing them from the system won't stop you reinstalling them, if you really have trouble with temptation).
OK, rooting the Pixel 2 genuinely shouldn't be hard. "Magisk" is the trickiest bit, but that's the new rooting method that allows you to avoid some of the drawbacks of older root methods, so probably worth following. There's a pretty detailed guide
here. It's changed a bit since I last rooted, but by my reading you need to follow the steps of installing fastboot and adb on a computer and rooting using Magisk (which at one point requires you to use "fastboot flash", which for anything other than official firmware means the bootloader must be unlocked). It seems you can do this without installing TWRP, though you will need TWRP if you want to try custom ROMs or ROM backups (without a ROM backup, called a "nandroid", be careful about what system apps you remove since any error will leave you unable to boot). The "flashing factory images" section isn't needed if you are already up to date with system updates, but may be useful if anything goes wrong (such as removing the wrong app, as mentioned above).
Note that I expect that rooting will break installing of over the air updates (I'm sure that if you then delete system apps it will). You'll still be able to update using a computer by flashing stock images, but you'll probably lose root when you do that and have to repeat the magisk step.