The answers a security review asks for
Hosted on OVHcloud in Germany, or on your own server under one licence for everyone. The audit log, roles and record-level rules are on every plan; single sign-on and scheduled backups come with the Enterprise licence.
In Airtable: Governance and security, Enterprise Scale

Your data in Europe
The hosted service runs on OVHcloud in Germany.
Or on your own server
Docker or a plain LAMP server. The Community edition is free; the Self-hosted Enterprise licence is per instance, not per seat.
Single sign-on and two-factor sign-in
OpenID Connect single sign-on with the Enterprise licence, and two-factor authentication with one-time recovery codes for everyone.
Append-only audit log
Who changed what, from what, when and through which app, with export.
Roles and record rules
Owners, contributors and read-only people per workspace and base, table visibility, and rules on which records each person sees.
Backups and trash
Backups of a base on demand, scheduled encrypted backups with the Enterprise licence, and a 30-day trash for what people delete.
Start with a base you already have
Bring it from Airtable with every record, link and formula, checked against Airtable. Free, and Airtable stays as it is.