Lost PST

[sidr]

Our ISP is phasing out their email addresses, and I am looking to use a gmail address as my default email inside superior MS Outlook 2019 (much better than gamil website).
However, when I went to start a new account, it started a new PST, meaning I effectively lost 20+years of emails from old ISP which I need.
So I had to change back to old email address to get all my old emails back from old PST.
Is there some way I can start a new account in MS Outlook, then import all my old emails & "lost" PST into that new account?


Any help appreciated.