Tried with Tools > Language > More dictionaries ("Dictionaries"), Gallery ("Gallery"), File > New > Manage Templates ("Templates"): in all cases the dialog shows up, loading is shown for a few second, but dialog remains empty.
Build ID: 663aab4c2dd5d64d49b91a30cfa8f057729eae36
CPU threads: 8; OS: Mac OS X 10.15.7; UI render: default; VCL: osx
Locale: en-US (en_DE.UTF-8); UI: en-US
Stephan solved the issue
*** This bug has been marked as a duplicate of bug 137922 ***