Solo founders do best when their stack is compact and reliable. The goal is not maximum tool count, but maximum clarity per tool.
Use a few clear layers
Pick a workspace for notes, a system for execution, a backend for product data, and a small number of automations.
If a tool does not remove work or reduce confusion, it probably does not belong in the stack yet.
Build around repeatability
The stack should support weekly rhythms: research, planning, shipping, and review.
When the stack is small, it is easier to maintain and easier to teach someone else later.
The solo founder stack should feel boring in the best possible way: clear, resilient, and easy to revisit every week.