I don't know how universal is this but in my country there is a proverbial saying " learn a craft and leave it, and when hungry squeeze it". Since here the "craft" is personal networks, and personal networks do not let you "squeeze" them easily once you have "left" them, then reviewing papers every now and then should not be too heavy an investment in an uncertain prospect -which could be returning back in science, but also it could be something else you cannot imagine right now. Ask any freelancer.

Do the editors know that you have left your scientific career? If yes, their invitation may say something about their opinion of you. But if they don't know it, I would suggest to make it clear right now: if they are happy to keep their invitation standing, then everybody knows you are doing them a favor. If they want to recall their invitation in light of this information, you will avoid possible later embarrassments.

I don't know how universal is this but in my country there is a proverbial saying "learn a craft and leave it, and when you're hungry squeeze it". Since here the "craft" is personal networks, and personal networks do not let you "squeeze" them easily once you have "left" them, then reviewing papers every now and then should not be too heavy an investment in an uncertain prospect -which could be returning back in science, but also it could be something else you cannot imagine right now. Ask any freelancer.

Do the editors know that you have left your scientific career? If yes, their invitation may say something about their opinion of you. But if they don't know it, I would suggest to make it clear right now: if they are happy to keep their invitation standing, then everybody knows you are doing them a favor. If they want to recall their invitation in light of this information, you will avoid possible later embarrassments.