Hi Wired_Peak,
Welcome to Microsoft Community.
I'm Hahn and I'm here to help you with your concern.
To permanently set the priority of a program in Windows 10, you can use the Registry Editor. Here's a general guide on how to do it:
How to Permanently Set Priority Processes Using Registry Editor - Microsoft Community
Disclaimer: Generally, modifying registry subkeys or work group is intended for advanced users, administrators, and IT Professionals. It can help fix some problems, however, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For further protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs.
This method should allow your settings to persist even after a restart. However, keep in mind that setting incorrect values or editing the wrong registry keys can cause system instability. Always proceed with caution and ensure you're editing the correct keys.
I hope this helps. If there is anything not clear, please do not hesitate to let me know.
Your Sincerely
Hahn - MSFT | Microsoft Community Support Specialist