Should I target users already on project management tools, or those not using any yet?

I’m building a project/task management app called SelfManager.net.

One thing I’m not sure about yet is my target audience.

• On one hand, I could focus on users who already use project management platforms (Trello, Asana, Notion, ClickUp, etc.) and try to convince them that Self-Manager does things differently.
• On the other hand, I could focus on people who don’t currently use any project management tool and are still managing things through notes, spreadsheets, or memory.

I don’t have data yet on which approach works better, so I’d love to hear your opinions:
👉 If you were launching a new productivity app, would you target users switching from existing tools, or new users who’ve never tried one?

Any thoughts or personal experiences would be super helpful.