why is my Visual Studio 2019 Pro so slow debugging, after doing Visual Installer update?

The resolution I found was that the culprit is not Internet, RAM, or CPU.

It is the Disk Usage. Check for your disk usage under the Performance tab in Task Manager. Try and find out which process (Anti-Malware/ anti-virus/ant other process) is eating up your resources.

Kill the culprit and it works smooth. For me, it was Disk Scan Service and Windows Search Service (which is fairly useless).

Check this link to kill the Windows search service.

Comprehensive deletion of all contents of %TEMP% worked for me - https://developercommunity.visualstudio.com/content/problem/516141/very-hight-cpu-usage-by-visual-studio-2019.html

I can't believe is 2020 and MS can't stop spaffing crap into a temp directory which causes their software to slow to a snails pace with some kind of infinite processing issue. Jeez.