We have not migrated a customer away from ClickUp, so this is a description of the work rather than a case study.
Expect to keep one system for the money
ClickUp does not invoice, so moving every tool into NoxOrigin is rarely the question. The realistic first step is moving the client-facing work: leads, opportunities, active projects, quotes, and open invoices. Internal task lists can stay where they are if that is cheaper than re-training everyone.
Map statuses and custom fields before importing
Task statuses, priorities, and custom fields are where migrations quietly lose information. Write the mapping down, decide what you will drop, and import open work first. Closed history is optional and rarely worth a painful cleanup.
Know which rules you do not have
Rules that fired on a task update in one system will not fire in another. NoxOrigin has no automation rule engine today — no triggers, conditions, actions, or run history, and no plan adds them. What it has instead is a record you can see: the next action on an opportunity, the project it became, the invoice it raised, and the payment state beside them. Where the rule engine stands.
Decide the client master record once
If a ClickUp workspace keeps external collaborators and guests who are not customers, keep that separation. Map customers into NoxOrigin as companies and contacts, and leave guest collaboration where it already works.