How to kickstart a growth plan for a 0-1 startup within the scope of the product team?

PLG is technically effective when a product has achieved product market fit. Running experimentation when you are still finding out the right types of audiences is not really recommended.

However, you can always imbue your early product with PLG concepts through freemium / trial experiences, frictionless signup and onboarding, and in-app messaging. Even though you may not be able to run statistically significant experiments with large effect sizes, you can still bring the ethos of that through constant feedback loops (private betas, in-app quick surveys, user testing) and hold out groups (e.g., run an experience to 90% of your users).

Always keep your backlog of design ideas (the ones that might have been in the top considerations from a design standpoint) and maintain your learning agenda (what do you want to learn about your users and your product direction). And most importantly, be open to changing your own mindset, let the data speak. Just because you had invested a lot of time and effort to go with a certain product direction, doesn’t mean it’s the only way.