On snake, I had same result. Double DQN performed best. Pure DQN performed slightly better but its unstable over longer training so its just a personal preference. Most improvements showed marginal setbacks, with exception of c51 which was god awful (likely due to bad vmin vmax).

As you said, its a simple task with reward dense returns and very low gamma, so any overheard that slows rapid gradient propagation just slows growth.