Dear Suresh,
Good day! Thank you for posting your query in our community.
I'm afraid that the SharePoint Online UI may not have an option for you to check which files are uploaded successfully. The only workaround at your side I can think may be that you may manually access the folders, export the files' metadata such as file names and so on as a .cxv file or use SharePoint Online Management PowerShell to export the file lists in a .csv file to an Excel file, get the local file list in the folders and export it as a .csv file and finally use Condition Formatting to find the non-uploaded files.
Another way may be to involve some logs for our related team to further investigate it.
From your description, it seems that you are the administrator and you have opened a ticket to our related team in the Microsoft 365 admin center. If yes, I suggest you follow up on the thread with them for further analysis. Sorry for that our category may have limited resources on further checking the corresponding logs.
Thanks for your understanding and have a nice day!
Sincerely,
Cliff | Microsoft Community Moderator