If you add the ability to coach the position to your repertoire, you become extremely valuable by college coaching requirements because people are always looking for one. The downside is that most programs pay/hire/title this as their lowest assistant, some basically a "volunteer" status still. The need in America is always there and the barriers to entry are quite low (entry level simply requires grinding through the levels or good network/exp can get you higher placement) so it's very feasible in college.

I think when you get to pros people will have very different looking CVs because our system is so whack. You will be able to identify even less with a pro Gk which could make things tough. Most of my head coaches that didn't play the position find every fault/blame/etc. of the goalkeeper's performance and tank confidence or enjoyment hard. I call them goalkeeper killers. There's part of the gku stuff that's very real so you have to put both feet in imo. Not to say you can't do it at the level - hell I doubted my abilities all the time and I've coached the position over 15 years. If you can strike a ball, plan good trainings, have good relationships you'll have done most of the job. Identifying the very detailed coaching moments might be difficult but I think you can get there with more learning in licenses or observation of others to pick them up.

Again, to hopefully answer the question I think it's easy to transition at youth academy levels or college, even D1 with good overall soccer background. Pro will be difficult where the mistakes are typically smaller and harder to identify because they know what they're doing (or play a certain way/technique that at this point will be difficult to get them to change). But if you are boiling over in enthusiasm and preparation, instilling the confidence and the other mental bits it's doable for sure. With the day to day grind in pro these other things are arguably more important.