The core decision is how much of your accumulated advantage you are willing to convert into starting capital for something else. Every mid career change involves a conversion rate. Moving to an adjacent function in the same industry might preserve most of your value. Moving to a new industry in the same function preserves a different portion. Changing both at once usually resets you close to the bottom, which is survivable but should be a choice rather than a surprise.
The second decision is what you are actually optimising for. Autonomy, meaning, income, stability and interest are all legitimate and they conflict. People who move without naming the priority tend to solve for the thing that was most painful recently, which is often not the thing that will matter in five years.
Age itself is a smaller factor than most people assume, and a real one. Experience is genuinely valuable, and it also raises what an employer expects you to already know. The practical consequence is that a career change at 40 or later works best when it is framed as applying existing judgement to a new context, rather than as beginning again.
Price the move before you commit. Compare the target role's realistic entry pay, a pessimistic estimate of time without income, only the retraining costs that actual vacancies require, and the likely time needed to recover your current earnings. This turns an emotional leap into a decision with visible constraints.