I want to say 1 but if I'm being honest: - Mining centralization (critical and not discussed enough, we should pressure the miners to adopt stratum V2 and DATUM) - Quantum Computing (not too much concerned honestly but we must continue to discuss and research on the topic) - Institution capture through paper bitcoin (this one is concerning only on a short to medium term but it could lead to a critical lack of interest globally, prevent bitcoin to stay the best store of value, create a vicious cycle of underperformance and lead to a very painful bear market until we reach the floor where only hardcore believers hodl it) - The rest is just noise to me So like 2-3 long-term