Ace0Spades

You have no promotable values in clubs or diamonds, just aces. Your spades have good filler cards. KJX is usually not as good as it seems. Often it goes small to the A and small back through the KJ with the Q on your left, but in fact either Q or A on your left means one heart stopper. 2S is correct.

Why west would bid spades is beyond me here. 1♦ - 3♥ (splinter)-4♥ (redwood) -- 5C (3 controls) -- 7D (12 top tricks plus the Q that partner needs somewhere for this bid.) Don't worry, nobody else bids their damn slams either!

I don't hate 1C. You need a raise from partner to make 5C, and someone bids hearts most of the time. After 1C-2H-2N-P you should be suspecting 12 or 13 tricks in clubs or diamonds if you find a fit. Parter has 10-12 pts, didn't double and has likely a lot of room for cards in the minors. After 3D-P-3H-P-you can either A) just bid 7D since you're a strong favorite or check again with 5H-P-5S (0 keys outside of H, no Q or extra length) - P - 5NT (Other Ks?) - 7D (I have everything and the kitchen sink).