“The plan didn’t work” is a full sentence. The next plan starts right after it.

A plan not working is a result rather than a confession, and it does not require the long story people attach to it. Most of that story exists to manage how the failure looks, which spends energy the next attempt needs. Stating it plainly is faster and, oddly, sounds far more capable than the explanation would have.

When the next one falls over, say the flat version out loud and move straight to what you will try instead. Take an evening to feel bad about it if you need one. Then start the next plan, which does not have to be dramatically different.