It'd be great if there were some handing of YT video ids in Lemmy, which would be independent of the provider domain. So like in Lemmy you could link to a YT video by the id (not URL), and then based on the user settings, that would open up in Piped or Youtube based on preference. I guess this could be done client side, and rewrite youtube links, but then for people who prefer Youtube and get a piped link, you'd need to know to rewrite that link. Anyway, that's the society I'd like to live in.
Asking individual users to make that kind of change is bad UX. Better if you got the client-side change based on use preference, even though users just post the normal YouTube link.
"Society if Piped would actually play videos," for me :( I've had some luck with Invidious, but I haven't been able to get videos playing on Piped for some months now.
The bot could link to the thumbnail using image syntax !()[] and add the title, channel, view count & duration; Piped even supports DeArrow for clickbait reduction. However, this would either cost privacy by auto-loading content from Google or add even more load on the "default" piped.video instance. Many people would also hate it even more for that.