SharePoint Online - Issue opening PDF's in Desktop app

Hi all

I have been trying to troubleshoot the issue of opening PDF files via SharePoit using the desktop app. I have searched high and low but have not come across a permanenet solution. One of the strangest things is that some users can open PDF files via Adobe Acrobat without issues, while others cannot and it seems to open via the web browser as default, here is a list of everything I have done to troubleshoot this issue:

1. Changed the settings in SharePoint for all documents to open using the desktop app

2. Acrobat has been changed as the default PDF handler in Windows 11

3. Removed Enable Protected Mode at startup in Acrobat

4. Enabled Adobe Acrobat for Microsoft 365 for the whole organisation via Integrated apps

4.1 Once this had been depolyed this had a mixed bag of results, some users could open PDF's on the web via Adobe but when trying to open it using the open in desktop button we were met with the error: There was an error opening the document, The file name, directory name or volume lable syntax is incorrect

4.2 I tried different browsers such as Chrome, Edge and Firefox and was again met with mixed results some opened in Acrobat on the web and some just opened in the browser, I have tried to check the settings in the browsers still had issues

5. Raised a ticket with Microsoft support and after doing their investigation they had advised to Enable Apps that don't use modern authentication (We will not allow this die to securty concerns)

Does anyone have anything else I could try to get this running consistently?

Thanks