In the last month or so, my VS2019 startup has been getting slower and slower. Opening a mind-sized solution (~50 projects) used to take a couple of minutes, now it's taking >15 minutes. Is there a way I can get "behind the scenes" and see what it's doing that's causing the slowness?
Historically, Visual Studio has problem with some browsing databases growing out of control. There was an infamous *.ncb file (Non-Compile Browser?) in VS 6, that periodically needed to be deleted. People wrote plug-ins and macros to "nuke" that file and seamless reload a workspace. Apparently, some issues were preserved for over 20 years.
Modern versions of Visual Studio keep those databases in the hidden .vs folder in your solution directory. You can simply delete this folder, it will be re-created as needed.