After trying many tools I found the best solution: eSoftTools OST to Office 365 Converter tool. It can import Outlook files into Outlook 365 without making any changes to internal data. It is compatible with all Windows and MS Outlook versions - XP, 7, 8, 10 and 2007, 2010, 2013, 2016, 2019 etc. This tool can import all internal properties into MS Outlook software. It’s 100% tested from anti-virus and online scanners. It can also convert OST files into many formats such as PST, EML, EMLX, MSG, MBOX, OFFICE 365, HTML, MSG, vCard, etc.
Read More:- Import OST files into Outlook 365