Having a well paid side-hustle while working in tech leadership

I have been running a side-hustle SaaS for the last 7 years that has finally reached mid 6 figures. I am in a niche so further growth is unlikely. My time commitment is probably 10h a week (weekends) and I have one employee.

I do have a full-time career as a tech exec with mid 6 figures as well and maybe on the path to low 7 in the next 5 years.

I generally love to work and don't plan to stop, I am pretty good at avoiding burn out.

I do have a question for those who build a successful side hustles. Once your business started to generate a more serious money what did you do ? I do understand the general options (save cash, sell, reinvest to build better product) but looking for people stories to give me some food for thought. Leaving the job is not an option as I thrive working with people and running a small company would not work for my personality.

The only non-trivial idea that comes to my mind would be to reinvest all profit into hiring few employees on a crazy moonshot/research project that could potentially lead to serious money but this opposite against all my previous business experience (slow, steady growth with very efficient cash management)