import the video from your device. cut out/speed up the boring parts. add a voice over or music or corrections to dialog. add intro screens, cut screens, transitions, titles. tweak the audio, censor curse words if required. insert images or screenshots you reference. insert labels/graphics. export it. re-export it because you screwed something up. upload to youtube. fill out their required forms. write description, timestamps, link cards, end cards. create affiliate links if that's what you're doing. follow up on social media. etc. etc. etc.

you're probably thinking of streaming, which involves less work, but you have to do it in real time with OBS or whatever. maybe you're talented and can do it yourself, but sometimes that involves a second person at the controls.

sure you can just upload a raw video straight from your device. but this is exceedingly rare, because you've grown accustomed to at least the basic round of editing - you likely don't even realize what edits have happened. raw video is incredibly boring. will anyone watch it? if not, then what are you even doing that for?

you should try both sometime, it's not quite as easy or fast as it sounds.