Clipboard Manager not copying Screenshots

That is very strange. Maybe the clipboard manager database is corrupted somehow. You can reset it completely by deleting these files:

'/Users/yourUser/Library/Application Support/BetterTouchTool/BTTClipboardManager_20241210.sqlite'

'/Users/yourUser/Library/Application Support/BetterTouchTool/BTTClipboardManager_20241210.sqlite-shm'

'/Users/yourUser/Library/Application Support/BetterTouchTool/BTTClipboardManager_20241210.sqlite-wal'