Quantitative:
1. Bid-ask spreads
2. Market breadth
3. Cross-Sectional Return Dispersion
4. Average Pairwise Correlation
5. Liquidity on smaller projects
6. Volatility on other coins than BTC
7. Trading expectancy on simple models
8. Momentum persistence
...
Qualitative:
1. Talking to other trading teams
2. Talking to allocators
3. Talking to capital introducers
4. Potentially - measuring the activity on X (we don't do that)
The thing is that usually, the biggest returns can be made from the change of the regimes. Being out completely is probably not the smartest way because one can miss the initial momentum wave.