Can I move from Shopify to Magento? How long, how much, how risky?

A move is feasible when the required data can be exported, mapped and reconciled. Start with sample products, variants, customers, orders and useful URLs. Identify account-access changes and payment or subscription data that needs provider-specific handling. Then test the ERP handoff, checkout, redirects and order reconciliation around cutover. Cost and duration depend on those findings and the storefront scope. Request an estimate after discovery and a rehearsal instead of relying on a standard number of weeks.

Official references: Shopify Admin API; Adobe Commerce and Magento APIs.