Hi
@Duc Nguyen
Unfortunately, the Computer is designed in such a way that, every time we change the display settings you have sign out of your Computer to apply these changes unless the preset ones.
Having done a lot of research for you, the issue that related to add customized scale to windows 10 without log out is still unsolved even in win10 21H1
If you google it, you can find many questions similar to yours.
Here I quote some links that might includes an plausible solution or an eclectic method.
In the below link, solution is related to office365
https://answers.microsoft.com/en-us/windows/forum/all/log-in-log-out-fatigue-and-custom-scale-set/1b26fb8f-2de8-4e64-856b-8eead954eddc
in the below link, solution is related to edit the registry. remember to backup before editing.
https://www.tenforums.com/tutorials/5990-change-dpi-scaling-level-displays-windows-10-a.html
Note: Since the websites are not hosted by Microsoft, the links may change without notice. Microsoft does not guarantee the accuracy of this information.
Hope this can help you
If your need further help, be free reply to me at your convenience.
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