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If you are using native Airtable forms, keep in mind that the forms only create new records. They cannot be used to edit existing forms.
One method would be to use two linked tables. The first table has the first set of questions. The second table has the second set of questions. The tables are linked with a linked record field. After the first record is created, it uses a formula field to generate a prefilled url for a form for the second table. The prefill includes a unique code for the first record, such as the record id. The second user fills in the info in the second form, leaving the prefill alone. Finally an automation uses the prefilled unique identifier to link the second record to the first record.
If you want to use a third party system for editing records, you can do that as well. Each system has its own method for ensuring that users can edit only the records they should have access to.