The main learning I took away from growing from 20 to 250ish employees, 1 product to multi-product and 1 geo to multi-country:
As a startup, your speed of execution is a function of your simplicity. It's about your only advantage over the big players.
Adding employees, adding products, and adding new markets increase your complexity non-linearly. ie. Going to 1 product to 2 products doesn't increase complexity by 2x, it increases it by 4x.
Avoid this complexity if you can: it makes you slow, makes you hire middle management, and makes what could/should be simple decisions, multi-dimensional.
So the lesson: stay as simple as you can for as long as you can. If you can't stay simple, don't underestimate the exponential drag of complexity.
Hope that's helpful
Do you think multi-country adds so much complexity that you shouldn't explore it too early?
E.g. What if you have an incredible opportunity in another geo? Should you put it on ice? How long for?
For us, multi-country added a lot of complexities because we expanded from the UK to Australia. So we needed to staff and integrate different teams (which is where most of the complexity was).
If you're a pure SaaS with no sales GTM, I think it would be a lot simpler if you can stay centrally operated.