I had that exact same issue after upgrading to the latest Windows 10 release 1909.
The icons spacing was messed up. Icons in programs looked wacked too.
Also from time to time for no reason my system DPI changes. I suspect bad GPU or a bad displayport cable.
There's a small program that I use called DesktopOK - it saves your icons arrangements, so you can restore to previous arrangement map.
Download at: https://www.softwareok.com/?seite=Freeware/DesktopOK
DesktopOK also has a tool called "Windows Metric" that can modify your Windows icons spacing.
Before you proceed with the next step make sure you save all your work and close all your programs, because to apply the icons spacing change you will have to restart the Windows Explorer and this process might close/terminate some of your programs and you may loose your work.
From the menu go to "Tools" > "Windows Metric". Press the "Default" button and then press "Restart Explorer".
Now all your icons should be returned to the default spacing.
Here's a guide at SoftwareOK: https://www.softwareok.com/?seite=faq-Windows-10&faq=109
Icons in programs should also be back to normal spacing - e.g.: AIDA64 Extreme, and any other that have icon based UI.
For best results do a system restart to clear any cached items!
P.S.: The best thing using DesktopOK is that you don't have to touch the registry!
Also do this at your own responsibility. I'm not responsible for you using this software!