Typically casino offers a feature that you can forfeit bonus and withdraw the deposit amount if you cant finish the wagering. I probably skipped claiming this 300% deposit bonus that I won on the contest.
I think your decision to ignore the bonus is a good decision rather than having to force yourself to use it without being able to forfeit the bonus later, and having to fulfill all the rules that are unpleasant for you, and winning a contest with a prize in the form of a deposit bonus does not seem like a prize because you who get the prize have the opportunity to lose money because you are chasing to meet the wager requirement.