I don't think Trump can just cry socialism and all the sudden Cubans who voted for Hillary are in Trump's camp. This is partly a generational shift and a long term problem for the Republicans in Florida. So while it could get slightly more Republican in 2020, I doubt it's by a substantial margin or by a margin that makes or breaks the state at large.
But it COULD matter in a razor-thin race, AKA Gillum and Nelson 2018.
Yes, it mattered in those, but if Trump is doing better in Miami-Dade than he did in 2016, it's unlikely the rest of the state swings that much left to make up the difference.