N64 resolution (for the vast majority of games) is 240p which is basically the same as SNES/Megadrive give or take 16 lines. At the same time, it was released in 1996 (at least in the UK) and CRT display technology was in rude health.
Long and short of it is that in terms of CRT shaders there’s not much of a difference between N64 and previous gen.
I wouldnt recommend using a ‘480p’ shader for anything that isn’t 480p content (very little). I personally wouldn’t go for straight upscalers either as you’re essentially just replacing one upscaler for another (a CRT shader is just a fancy upscaler tailored to retro games). Also original content is very low ‘quality’ compared to modern ideals but that is totally subjective and far be it for me to say what someone should prefer or not.
Anyway I think you know this already but for the purposes of others the Sony Megatron in the HDR folder will simulate CRTs of the time pretty well but you will need a bright display.