r u using current firmware 2.0.4? that should be fine.

i assume u mean local playback with kodi n wrapper and not online kodi streaming.
but why play via kodi with wrapper when u can play direct with himedia player?

I think i misunderstood u or u hv mistaken...

When u say use kodi wrapper, do u mean set wrapper app to kodi player or wrapper player?

Also, do u mean how to load srt file u already hv or download online as u play?

2 things strange here..

1. if u set to wrapper player, local playback via kodi will just send the data to be played with native player.
i.e. same as using native player direct.
u do not get the kodi menu to load subs the kodi way.
u load subs the same as when u use native player.
so, if u can load subs with kodi+wrapper, u can do the same when using native player direct.
so, i don't understand why u can do with one and not the other.

2. when playing with native player, pressing the MENU button at the center lower right of the remote will bring up all the options -
audio, subtitles, picture quality, etc.
under subs, u can choose any sub that is available.
by default, it will read ENG SRT.
so, if there is an SRT file there, it will read it.
this default srt sub reading feature has always been there, since previous models.
so, i don't understand why u can't get it.

nas or internal hdd or usb hdd, there should be no diff for playback with native player.

if all the above is correct, i can only suspect your 2.0.4 firmware was not installed properly.
i hope u had done correct progressive updates steps and not e.g. jump from old android5 1.0.5 to android7 2.0.4.
wrong sequence updates will certainly cause strange problems.

lastly, best for another q5pro user to commnet as i am using q10pro.
but as far as the subtitles feature is concerned, it should be exactly the same.