If you have several npm packages inside the same "monorepo", you and your users would probably be better off if this was one big coherent package instead.

1. A lot of bookkeeping and administrative tasks just disappear.
2. Three shaking removes unused code either way.
3. Unhealthy dependencies between each package is impossible, because everything is just one single dependency.

Instead of "monorepo", consider a monolith instead. That is, one huge application. It solves the same "issues", but with a lot less administration between the teams sharing the components.