One thing I did not expect as a solo founder:

building the product and learning distribution feel like two completely different careers.

You spend months solving:

architecture
UX
latency
onboarding
edge cases

Then after launch you suddenly need to learn:

positioning
storytelling
audience building
content
retention
psychology
community

Feels like modern founders are forced to become:
developer + marketer + designer + storyteller at the same time.

What skill outside of building surprised you the most as a founder?