Scaling Problems using 4K Monitor

I saw a great deal on a UHD monitor and grabbed it, completely unaware of the issues regarding scaling for programs, particularly older programs, in a 4k environment.
(For those who also do not know: this is when a program opens and is so tiny on the screen you can't read anything, or it opens in a normal sized window but the text is so tiny you can't read anything.)
I took the crash course (otherwise known as Numpty School) and corrected a few things.

• Windows Settings > System > Display > Custom Scaling Settings. I use 190. Seems good.

But this does not work with some older programs, so...
I also did the "High DPI Settings" trick:

• Find the programs .exe file > Properties > Compatibility Tab > Change High DPI Settings >
• Program DPI > check: Use This Setting…. (Note: “Open Advanced Scaling Settings” just opens the W10 General Settings listed above)
• In drop down for Use DPI Settings that’s set for my main display when: change to: When I open this Program
• High DPI Scaling Override > Check: Override High DPI Scaling Behavior > Performed by: Change to: System.
• OK > Apply > OK

This works great for some programs but not all. Plus I need to do this for every program with a problem one at a time. Any easier way known?

But some programs don't use exe. They use dll. And they are freaking out.
I found this fix below, a registry edit:

• Registry > HKCU \ Software \ MS \ WindowsNT \ CurrentVersion \ AppCompatFlags \Layers
• Add Key: C:\Windows\System32\rundll32.exe > Set Value to: HIGHDPIAWARE

Is this a good fix for this problem? Does anyone know of a better, more permanent, or more universal fix?
Thanks

The above registry edit seems to work. No problems to report as of now.