Why not have something moveable underneath to support it? That string seems impractical in general.

You’re going to find that edge and/or corner one night and you’re not going to have a good time.

Doesn't that get in the way while sleeping? Don't you ever knock it down?

What I would do is connect it the opposite way round. So that it folds down, not up. Give it a little leg that folds out when you pull it up.

The leg could be done in a few ways. But I would prefer it so that it is connected to the table top's underside on a hinge. So, when the table is folded down the leg is tucked behind it, and when you pull the table up, the leg "drops" down and upright.

• The board is not supposed to go up while I'm sleeping 😅 it's mostly for cleaning etc (which is probably why I thought of folding up first). The hinges are a bit of a gimmick, not strictly necessary, but I really wanted the option to fold it in somehow, make it not stick out when needed.
• When folded in, it would be less in the way if folding down instead of up - but that would a) take away the space where any wooden leg/support could go while also b) making the cord solution impossible.
• A leg would indeed be a sturdier support ofc (and would provide a better justification for the fold-away feature). I'm thinking of adding one underneath attached to another hinge. However, I like the string for minimal use of material, and there doesn't seem to be weight problem with it 🙂

Maybe reverse the hinges so it swings down and out of the way. You might hurt yourself on the board sticking up when sleeping.

Perhaps you could try a farrimond friction hitch on both ends? It fits a+b and it has a quick release