If there is an opportunity to change the culture from within, you should consider that first. I’ve done some recruiting and I’ll admit the short stints don’t look great on a resume. It makes you seem like someone who is more willing to run from a problem than to try to fix it. Keep in mind that you may not need permission to do some of the things you want to do. Dress down a little - see if anyone cares enough to call you out. Set aside a few hours for innovative work. If you can’t get anywhere with that, then I’d agree - time to look for another job, and best to be honest about why you’re leaving. If you can speak to some of your efforts to improve the situation before bailing, that could definitely help to quell some concerns about your commitment.