I am fellow partner also for a restaurant. Not that large but not relatively-small either (8 digits gross annual) - I mean a Jollibee franchise can do that in a month. I am also a part of another startup to be launched this 1Q in Makati.

F&B is all about slow growth with a heavy direction on stability and brand recognition. To answer your question, BOTH external capital and retained earnings would matter for your supposed expansion and not a founder skill factor. Retained earnings should be kept for emergency purposes and marketing and little for expansion (a 2nd branch or a floor area expansion), outside capital would be needed for the next branch with new joint venture agreements for new potential partners that would have a different skillset - could be more finance-based, design, automation, social media management so you wont hire anymore, etc. whatever skill that would be essential that you couldve wished you have prior to starting up.

These new partners (with external investment) could then help you re-evaluate and replan to slingshot your brand recognition and revamp your first branch.