Having issues migrating outlook (and associated pst’s) to a new computer. Months of recient emails are not appearing. to a -- 2

Hello, I have recently been dealing with a difficult issue relating to migrating Outlook and associated pst’s to a new computer. The problem I am having is that months of recent emails have not been appearing. Currently, I am using Outlook 2019 or Office 365, and have tried several troubleshooting steps to try and resolve this issue, however to no avail. The size of my PST file(s) is 50gb. I am looking for a freelancer with extensive experience with Outlook and migration who can help me resolve this problem effectively and efficiently.