ssshhhh, don't repeat this to anyone....
but there is an ancient, long forgotten path to avoid all this...
Go Back to the Days of actually posting Event Info (including levels & rewards) before actually releasing them...
Call me 'old fashioned' but, it used to work!
& armed with prior knowledge, I completed/attempted to complete more Events, than I do now...
Although, I appreciate that this is far too radical a suggestion for the custodians of our game...