Probably a bad time to suggest the Jellyfin for Kodi plugin (since they removed the network paths in this version) but it’s what I use for my main playback device.
All the goodies of playback via Kodi but play state and metadata gets synced from Jellyfin.
Another option of course would be to open the file(s) in MKVToolNix to add and correct the subtitle offset there.
Is that the native paths method they removed? I never used it and didn’t understand the reason for it, but I’m guessing its useful for some users?
Yep. Kodi slows down significantly if you have a large library and play through the addon. Native paths fixed that issue by playing directly from a network share instead.