Hi! Have you reviewed the options available in here:
https://support.microsoft.com/en-us/office/why-did-my-file-open-read-only-3ab4b792-da50-4b38-8628-14c64e1f1d15
You can also test a clean boot in case a third-party app is causing the issue:
- Press Start, type msconfig, and open System Configuration.
- Go to the Services tab.
- Check Hide all Microsoft services.
- Click Disable all.
- Go to the Startup tab and click Open Task Manager.
- In Task Manager, disable all Enabled startup items.
- Close Task Manager, click OK in System Configuration, and restart the PC.