i know it may not related to GOS but mabey it dous and let me explain:
step to reproduce
1) create a secondary user profile in GOS (on the main profile it works, subs download as expected..)
2) install vlc and search for subs for your video
3) there is a results but when you click to download the arrow icon turn to Circle (loading) and stuck
p. s.
i try it also on a lineageos and it works (subs download as expected on a secondary profiles)
that's why i think the bug did related to GOS..
and thank you for this great OS
links that have the same bug
https://www.reddit.com/r/VLC/comments/vpstde/subtitles_not_downloading_in_vlc_android/
if you needs logs i'll send to you in dm
and if it does bug in vlc im sorry for that post that's why i tag it in general and not in debug