Should I go for a promotion at work while starting a business?

I work full-time as a content designer and I’m in the process of starting a new business that helps underperforming websites improve their UX.The money and the job are good, relatively low-stress and healthy work-life balance, giving me the headspace to work on my business.But there are two new roles that have become available, both a pay band above what I’m on now (~£11k more a year). People are egging me on to go for it as it’s ‘more safe than self-employment.’ That aside, I’m drawn to it as I’d like to go part-time some time in the future as my business expands, and therefore the drop in pay will roughly meet what I earn now in a band lower.My predicament:Do I go for the promotion so that in a year or two I can drop to part-time while my business expands (and in the meantime to give me an extra cash boost to my safety net as I build my business)? OrDo I stay where I am so I can keep my headspace clear and low-stress while building up a business on the side?Completely appreciate that only I can answer this but I’d be interested to hear if other entrepreneurs have experienced something similar, and if they found it more beneficial to have the headspace to build a business from scratch at lower pay or to have an extra cash boost with a potential of burnout?Thanks! see hubwealthy.com/wealthy