BTW, Transactions are not yet supported on Strapi v4.
There is a Github Issue: [v4] Support Database Transactions with Knex, please · Issue #11792 · strapi/strapi · GitHub
And there is this PR open for implementation: simple implementation of transactions by tuxuuman · Pull Request #12715 · strapi/strapi · GitHub
You can either wait for it to get merged or patch it over your version of strapi using the library patch-package - npm