How to use Dovecot to serve through IMAP multiple maildirs ? Unify multiple mail accounts into one IMAP Dovecot

Hello,

Right now I have mail accounts from three different providers. I would like to set up Dovecot on a VPS so I can access my mail from there. My intention is to have just one account from which I can access all the mail. It being served by Dovecot through IMAP.

Is it a good idea to use isync/offlineimap to download the mail, and serve it unified using Dovecot?

Any documentation or information would be really helpful. I already have postfix with forwarding so I don't have to configure multiple accounts in my devices to send mail. But I don't see to grok dovecot enough to join my mail accounts and serve them through IMAP.

Thanks for any help!