Should I quit a job in a high demand field without something lined up? Details inside.

I work in a very high demand field and have been at my job for 2 years now (information security, this is my first job out of college). For the past few months I've been absolutely dreading going to work every day. I love the field but my current job is not what I had in mind. My boss is extremely demanding and has a short temper, and I feel as though the only thing I'm doing is testing new products for the company to buy. No creativity, no impact on policy, and for the most part just feel like a sysadmin which is not my thing. The pay is fantastic and the company is great, but I don't see my current situation changing any time soon. I've made some mistakes lately because I just don't feel invested in what I'm doing and that is adding to the weight on my shoulders because I know my boss has noticed. I'm not sure how much longer I can keep schlepping myself in there everyday just to go through the motions. It's really draining and taking a toll on my mental health.

I'm currently working on attaining a certification in my field in my spare time that is well respected (OSCP for anyone that knows the industry) and I've been loving that. My wife is encouraging me to maybe quit, work on the certification full time and then apply to new jobs once ready, I've just always heard that it's better to apply for new jobs when you are still employed. I have a little over $12k saved myself but have some hefty student loan payments. My wife comes from a wealthy family and has well over 100k tucked away in a tax deferred account (we would like to avoid using that if possible), but she works in a very low paying industry. This is a tough decision and I was wondering if anybody has any advice?