Facilitator laws shift collection for marketplace orders. They do not shift registration obligations created by inventory sitting in a state warehouse, nor do they cover your Shopify storefront.
Build the register once: every state where you hold inventory, every state past the economic threshold on combined or DTC-only sales depending on local rules, and the registration date for each.
The expensive mistake is registering late and voluntarily disclosing four years of exposure. The second most expensive is registering everywhere out of caution and paying for 46 filings you never needed.
