I am also having libraries/board manager stalling after updating to IDE 2.3.3. I use Debian 12.6 (Bookworm with kernel 6.1.25). I do not use the root account. I use the AppImage version of the IDE. Version 2.3.2 worked fine but not 2.3.3. I have compiled and uploaded code to an Arduino nano esp32s3 with 2.3.3 but only after closing the app and later re-opening. It seems that library/board updates get stuck after the load process. In this condition, it is not possible to compile/load sources. I note that updates have been placed in the '/home/redacted-user/.cache/arduino-ide-updater/pending/' folder whilst downloading/make executable places the app in the '/home/redacted-user/Downloads folder - I have 2.3.3. in both now! Perhaps I should place the app in the /usr/bin folder? The file 'update-info.json' in the above mentioned pending folder has nothing but the 2.3.3 appimage name, the sha checksum and user rights token so I do not think that is a problem.