Sometimes I will share a resource on YouTube here. I think it is good on its own for the community, but really its a good intro to share with friends and family.
People often push back because of the link being YouTube, fair, but simply saying find a front end is kind of entailed. Many that are public go down and never come back, and the link does have the video ID at the end of the URL so if you are self hosting you can just load it up.
The problem with a static list in a sidebar is exactly what you said: public instances come and go, and in six months half the links are dead and someone has to keep pruning them.
A lower-maintenance option might be to link to the things that track health instead of the instances themselves, e.g. the official Invidious instance list that shows uptime, plus a one-line mention of LibRedirect (browser extension that rewrites YouTube links to a working Invidious/Piped instance and rotates when one is down) and FreeTube for desktop, which doesn’t depend on any public instance at all. That way the sidebar stays correct even when instances disappear, and people sharing videos here can keep posting the plain YouTube link without it being a problem.