You are mistaken ppi and dpi, 1 pixel on screen will print with 4 dots with ink (Cyan, Magenta, Yellow, Key color), Canon photo printer have 12 colors so it have resolution up to 10000dpi, for calculation of ppi i wrote already. If you can't understand just remember 300PPI - is photo with very small dots what you can't see with eye, but it also requires special high density paper! and tone of inks, so it will never be print on the street banner fabric. Middle quality in magazine paper ~150PPI. And for street graphics what has big scale it requires strong material, banner fabric and it prints around 36-72PPI, if you print more it can't take so much inks and will bleed.
38211px is 1378cm with 72PPI, but you can make 36PPI and i am not sure about 1/10upscale, this is without upscaling, you can upscale with AI algorithm in twice without any notice, so you can reduce resolution even more