chamberlain was put in a situation where he knew dern well that england could not stop germany from taking czech-via. the only thing chamberlain could do was buy time for england’s rearmament program to reap results before going to war with germany.
maybe he got a bad rap, but i don’t think it was becaause of personal gullibility - he knew that britian could not force germany out without a war there was no chance of winning.
It's a complicated issue, but the only real argument should be over whether war in 1938 would have been fought more successfully than in 1939.
With Czechoslovakia and, potentially, USSR on the Allied side it is quite possible. However, France was, though nobody really knew it at the time, hollowed out by faction and defeatism, and USSR military was even more in turmoil from Stalin's purges than it was in 1939.
Interestingly, if Stalin had allied with UK, France and CS, there is some possibility Poland would have allied with Germany. Poland wanted its piece of CS, and for darn good reason was even more wary of USSR than Germany.