Improving work-life balance

My situation is: I've started working for the current employer in 2022 and they pay more than decent money. I was moved to a new project at the end of 2024, it combines every negative stereotype of an inefficient government/corporate system under the sun that just barely ships and I disliked it from the start. The change happened unexpectedly and coincided with exhausting events in my personal life. I really feel worn down. At the same time there's current market situation combined with my skill gaps. Many years of my Java career was in strange and niche stuff, only recently I've moved to web development with some limited frontend experience. There's only so much I can learn in the space of microservices, Kubernetes etc. on my own, but, again, poor work-life balance leaves me with little time and energy for self-development. The decent pay is also a strong factor as I plan to build a house. Chicken and egg kind of problem

Summary: landed in a bad project -> it contributes to poor work-life balance -> limited time and energy for learning stuff to find a better project.

I've came up with an idea to propose reducing my hours to work 4-day weeks and asked for a rise at the same time. both were rejected due to the business arrangement with the client, as I expected. They really don't want me to leave, which I know as it takes 2-3 months of paperwork to even join the project and then about 6 months to reach some kind of productive level. At the same they don't have much to offer me but encouragement to stay and some good words.

I never even hinted at wanting to change a job, but I am actively applying. At this time I have one pending application waiting to schedule a technical interview. I don't rate my chances to be accepted too high, but if that happened I would feel bad about leaving after this discussion.

Summary:

• if I stay:
  • I keep the decent pay
  • decent job security, replacing anyone here is costly and there are literally years of work already contracted
  • still have to figure out work-life balance
  • still lagging behind in skills
• if I leave:
  • possibly only for lower pay, but my initial offer was actually higher
  • almost guaranteed lower job security
  • unpredictable working conditions and work-life balance
  • typical transition stress no matter what happens
  • opportunity to reduce the skill gap
  • just plain guilt in relation to the people at my current project, I'm not a cold-hearted businessman

I'll be thankful for any advice or ideas to improve my situation at the lowest cost.