Another solid option worth adding to this list is EdbMails OST to PST
Converter. It converts orphaned, corrupted, or inaccessible OST files
to PST without needing Outlook installed, and it keeps the folder
structure, emails, contacts, calendars, and attachments intact. You
can preview everything before converting, and it handles large OST
files without issues. There is a free trial to test it on your own
file first.
Check for more details at:
https://www.edbmails.com/pages/ost-to-pst-converter.html