i'd probably say it's the other way around...
But neither of them are dumb either

actually you just want to be nice to papyrus because you have a decent mentality and it would feel bad to tell the truth

papyrus is not the brightest bulb in the box

No, i actually think that.
Just because he isn't the brightest bulb in the box doesn't make him an idiot

you could say he aint the sharpest tool in the shed

you could also say she was lookin kinda dumb with her finger and her thumb with the shape of an l on her forehead(all star)

papyrus is the sharpest tool in the shed

papyrus glazers out there calling papyrus the optimal being

HE IS THE BRIGHTEST BULB IN THE BOX!!! WHAT THE HECK ARE YOU TALKING ABOUT????

bro pretty much every other character is smarter than him (except Undyne)

Toriel can consistently remember the solutions to over 10 different puzzles and has been doing it for years without making a single mistake

Sans can perfectly predict attacks and can dodge them effortlessly even when he's tired

I don't need to explain Alphys.

Mettaton SOMEHOW figured out how to rearrange entire rooms without leaving a trace of his presence, and also figured out about resets somehow.

Asgore figured out how to break the fourth wall and effortlessly reduce the amount of options you have to 3.

I don't need to explain Flowey either.

frisk canonically can't count to 10

oh

tem went to colleg

i think you spoke of canon Papyrus. all I know is fanon

ah.

"I don't need to explain Flowey either."

yeah, you don't. Omega Flowey is NO JOKE 😭😭😭

he's stoopid but a kind stoopid he ain't let evil he just stoopid and still lovable and that ok:D