You can add "cards", i.e. the popups in the top right that show a short text and an "i" button. Those can be links to videos, polls, or external links (if you're a big youtuber). However the text is limited, you can't set how long it shows, and you can have a maximum of 5. You can maybe use subtitles too, but you cannot set a default subtitle for your video.
So there are hacky half-working workarounds, but otherwise youtube just told everyone who cares about their videos to go and kindly get fucked.
Who said anything about editing errors? I am talking about things like exploratory engineering videos, where the creator is speculating about certain things that get apparent only after the video has been uploaded, sometimes with the help of viewers.
It is for example not uncommon in teardown, some done by leading engineers in their entire field, to find out what some proprietarily marked chip is a few days after the fact. This is not a “fuck up”.
Reediting and reuploading a video just to change a single (but possibly important) detail is not only a colossal waste of time and effort that could be better spent on other videos, as far as I know it will also present itself as a new video.
So there are hacky half-working workarounds, but otherwise youtube just told everyone who cares about their videos to go and kindly get fucked.