Nothing lasts forever, take solace in that.
I think what could help right now is mentally separating money and work from your passion. You’re working now for a reason, till you can build whatever your passion needs to take off. Tell yourself it’s just a temporary source of income, never forget the larger goal. Make it clear in your mind. Create the path towards your goal. However small the goalposts are, do something towards it everyday. The longer we don’t pay attention to our true goals, the more our current situation weighs us down. This might require some extra time management, but it’s worth the effort.
Don’t let this office sway you into overthinking or being demotivated. It’s only temporary, but it’s easy to become stagnant even in a shitty job.
Advertising is a tough field to be in, if you don’t enjoy it. I’d say start looking for something closer to your passion + meets your financial requirements.
If you let the assholes get to you, they’ll drag you down to their level. Learn, observe, understand how to deal with people like this—there will always be something useful you can take back from a bad work experience. Do NOT allow them to influence you. Many people are demotivated, jaded and pessimistic, and will convince you that this is all life is. It’s not. Shoot your shot, bro. Don’t give up.
Find more encouraging people outside work to balance out the BS, truly does help.