If you are looking for free methods to import Google takeout data to a new account using the best methods. users can simply export the data from google takeout as MBOX, and then upload the MBOX file to the Thunderbird account and then connect the new account in Thunderbird and upload the MBOX file to new account.
If you want to step by step guide, then follow the mentioned page,
where you will get the free methods.

https://www.aurpo.org/import-google-takeout-data-to-new-account/