as you said, i think it is logic to use speed brake during speed exceedance.
But with the wing at high speed and probably with some G force due to high speed protection, is it a good idea to extend spoiler for the wing structure?
In the limit part of the fcom it is reported that there is no limitation in speed for spoilers......for sure inside flight envelope. Outside envelope is a duty of test pilot to understand what is going on and not for a stupid pilot as me.