Just to clarify: You were both at the same org level but you were the more senior developer and mentored them? Did you previously let your boss know you wanted

Just to clarify: You were both at the same org level but you were the more senior developer and mentored them? Did you previously let your boss know you wanted to move into management? Do you have significant experience remotely managing an on-site team? Since it is a small startup I'm going to assume "manager" encompasses a large number of different roles. In these kinds of situations I'd pick the employee with domain knowledge every time! It is critical for setting direction, analysing project requirements, dealing with other teams, dealing with customers, etc. Are they good at their job? Do they get along with the team? Do they handle pressure well? What do you mean when you say this other person has limited work experience? <6 months, <2 years, <5 years?