I agree with flare9x.

SPY is clearly mean reverting, at least for now...

In my experience, trying to determine market regime is quite unlikely, no matter how sofisticated your indicators are.

I´ve done a lot of trial with Hurst, MMI and so on and i can tell you the simplest and efficient way is just mixing mean and trend altogether or trying to adapt the exposure of each algorithm based on its own performance.

That is, if mean algo is performing badly, reduce lots or go phantom and viceversa.

We cannot predict future, just manage risk accordingly.

Just my two cents.