Hi Brother. I'm Greg, an installation specialist, 10 year Windows MVP, and Volunteer Moderator here to help you.
See here how to change default monitor:
https://www.tenforums.com/tutorials/3871-change...
Also helpful guides to setup and troubleshooting Dual Monitors to have handy:
https://www.digitaltrends.com/computing/how-to-...
https://www.windowscentral.com/how-connect-and-...
https://www.addictivetips.com/windows-tips/diff...
https://www.windowscentral.com/how-fix-your-sec...
I hope this helps. Feel free to ask back any questions and keep me posted. If you will wait to choose if I resolved your problem, I will keep working with you until it's resolved.
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