I’m facing a recent problem with 8.90.2, not happening with previous 8.90.1.
Kodi freezes when browsing my NAS for selecting media content.
I have tried with FTP (my first selection even with 8.90.1) and SMB, same problem.
Kodi screen freezes, so I have to reboot from ssh, even on screen debug messages get freezed.
Did you upgrade from 8.2? it looks like your box is looking for settings which don’t exist and it’s using all the CPU which would explain your directory browsing issues.
For subs a had this with other builds too. So i changed the path from „with video“ to a folder i made on the sd card … so the problem after 1-2 reboots was gone.