I deleted my account before migrating to bitwarden, several months ago. I hope it is actual deletion and not "soft" delete.
I always mail them for deletion of account and data on their server.
When I was organising all email IDs, I tried this mailing method for 10+ websites for deletion. Respective website's customer service replied to all mails and many of them replied that we can't delete data on server, not possible to delete, it gets automatically deleted after a certain time, we deleted your data.
Don't know if they've deleted it or not, but later I tried checking forgot the username/email feature on their website.