[MM3-users] Speed up importing mailman2 lists

We are currently planning to migrate from mailman2 to mailman3 as a container, have around 1500 lists and would like to complete the migration ideally in a few hours. We would like to switch off mailman2 to have a defined state of the lists and import them to mailman3. The import of all lists via script takes about 3 days. Parallelizing the imports does not work due to lockings in the database. However, we cannot accept a downtime of 3 days. Does anyone have tips on how we can speed up the procedure or are there best practices for larger environments?

Thanks and best regards, Thomas