Is there a program that will tell you the optimal algorithm for ANY problem if the problem is decidable?
As discussed in the comments, the question is not well-defined, since it's unclear what the input is.

However, under any reasonable assumption, no such program exists. One way to see this is through context-free languages: assume we can solve your problem even to the very restricted class of context-free languages. Thus, we have a program $P$ that given a grammar $G$, outputs a TM $M$ whose runtime is optimal (which is also not clearly defined, but let's ignore that for now) and recognizes the same language as $G$.

We can use this program $P$ in order to decide, given a CFG $G$, whether $L(G)=\Sigma^*$, by running $P$ and checking if it outputs a TM which is just a single accepting state (which is the only optimal TM under a reasonable optimality definition). Since this problem is undecidable, then $P$ cannot exist.