Comment by Swankivo

The three products you named each had a sharp, different target. Zendesk for support teams, Jira for engineering orgs, Linear for startup product teams. What's missing from your post is who your target is.

Who is the real target of the thing you're building? Not "we want to be an alternative to these tools," but the people who won't be satisfied by anything except your service. Put the other way around: who exactly are the people using those three tools today and still feeling the friction?

Only once you've pinned that down can you even start discussing marketing strategy, open source vs closed source included.