Photoshop takes a long time to startup while stuck at "reading preferences". Issue has started happening not so long ago, I suspect after one of the recent updates. Current version is 22.5.1, running in Windows 10 (Version 10.0.19043 Build 19043). I have tried all of the known methods like deleting the user profile and complete reinstall to no avail.
After extensive debugging I narrowed it down to these events from the UXP log file ("\AppData\Roaming\Adobe\Adobe Photoshop 2021\Logs"):
The time different between those 2 entries is always around 32-34sec. During that time Photoshop is actively writing to an LDB file in \AppData\Roaming\Adobe\UXP\PluginsStorage\PHSP\22\Internal\com.adobe.unifiedpanel\LocalStorage (file name is different every time, eg 000277.ldb).
So, looks like the delay is hapenning during that process. I have the same version of Photoshop on my Windows 10 laptop and it has no issues with loading.