Medicine. It's significantly harder than software engineering in terms of the lifestyle and demands on you, but I've never been happier or more fulfilled. A lot of the skills translate over, other than perhaps the actual coding.
Did my premed coursework a decade ago when I did neuroscience. Just needed biochem, and about 800 hours of self-study for the MCAT. Interview two weeks ago, fairly optimistic about this cycle but if not, I think next cycle will go well.
Everyone focuses on the amount of schooling and training that this requires. I am happy when I am helping people and constantly learning new things, and I'm already doing both.
There are a lot of other options than just med school, tbh you can make as much money with way less schooling as an anesthesiology assistant.
Once you finish med school, complete all of the exams (STEP?), get a residency spot, and finally become an MD (or DO). The challenge doesn’t stop there.
Now you get to deal with a whole another beast: hospital and clinical based medicine in a neoclassical economic setting. Your patients don’t matter. Their outcomes (unless sued) don’t matter. What matters is pumping your billings at the end of the quarter, dealing with endless amounts of paperwork with private insurance.
Healthcare in the US is a mess and I am glad I switched early before getting myself into $250K+ or more worth of debt (med school is expensive af).