Whether it's OP or not...can't really tell. In some decks that really need
that one card to work, it is extremely useful. Though in others it could be less useful.
Earlier you mentioned Limitless Speed as an example - for that specific deck it might be in the less useful category, at least based on my experience. More often than not I had to keep the dragon in my hand to protect it from CC, or could not play it due to lack of quanta. For Limitless drawing the dragon in the last turn is okay. You will probably win anyway, the difference is whether sooner or later (let's skip the part where you run out of dim shields)
On the other hand, if you run a Chimera based deck, it is the single most important card, so you would want to draw it as soon as possible
In short: it might be balanced as is, but I'll let the more experienced members decide that
