Leaving a job to pursue a PhD [D]

I have been working as a ML Engineer at a startup for 4 years and while the environment is very good and the pay is higher than average, I'm thinking whether I want to pursue a PhD. Working and doing the PhD at the same time is not really viable so this would also potentially mean quitting.

What I don't like about the job is that I'm actually not doing any real data science and modeling. I guess I'm working on more modeling and scientific questions than most ML engineers but I'm barely scratching the surface of each problem and most problems are resolved with quick and data-driven methods. Rarely do we apply novel algorithms or do real literal reviews and R&D.

Additionally a big part of my job is actually just developing software, talking with customers, DevOps and service reliability. While I like the fact that I'm working on a variety of things I don't really have the chance to deepen my knowledge to a meaningful degree on any. With agents writing most of the code and pressure to move fast, most engineering solutions are surface-level and really I don't think that I'm advancing my knowledge and skills. The only thing that I'm actually learning is how to work with agents.

Then of course it's the problem with AI and agentic coding. I deal with a lot of slop on a daily basis and although I'm careful with my job I inevitably produce a share amount of slop myself. This is what modern startups are forced into because management wants accelerated development and competition is high. I'm having real problems with AI fatigue and too close to burnout.

I miss the times when I could work on the same topic for days or weeks, research, read, plan, do experiments and iterate on the results. Then finally, hopefully, arriving at a hypothesis that works and finding a novel idea. However, it's been 4 years since my last real research experience, during my master's thesis, and I'm quite sure that academia has gotten worse due to high saturation and AI slop.

I really don't know about how the future will be but I think that being academically inclined and liking research I may be wasting an opportunity to do a PhD before I get older. Economically it doesn't make sense for me to do that in the short term and I'm aware of that and I don't have a clear career dream in academia but I feel that I may regret it in the future and blame myself.

Is anyone crazy enough thinking about moving to academia or having done that already? I would like to hear your thoughts.

P.S. I didn't use AI to write this up and I would appreciate human responses only