Hate my job, and have a 3 month notice period.

I don't really know what to do.

I used to absolutely love my job and thought I'd be here for the longterm. Recently, though, I got promoted and ever since that, I've absolutely hated it and I'm miserable.

I want to leave and start applying for new jobs but my current position has a 3 month notice period, which I know a lot of companies are going to have an issue with. I also know that the job market is horrendous and handing in my notice with nothing lined up is a huge risk.

I just don't know what is best here. Do I hand in my 3 month notice period and then use that time to finish out my current job and job hunt (I have about a years worth of rent saved up) or do I start applying now, hopefully find something, and then hand in my notice period and hope that the new company doesn't mind a 3 month wait?

I feel very stuck and I'm not too sure on the best course of action.

Thank you!