This has NOTHING to do with wicked.
Wicked makes no promises. All movies (from pretty much all IPTV services) are typically scraped from various sources and they are encoded the way they are encoded. It's the same rips you will typically find on torrents and other sites.
Your workaround, for looking for a player which will do what you want (external subs), has nothing to do with wicked (you'd probably want it regardless of the service you use - since I doubt there is any consistency for this ). As you already assumed, wicked will surely not be updating it's TB (of not PB) of media to include what you want. Some VOD (typically the 4K versions) have pretty much every sub you can think of (so it is NOT the entirety of WickedTV VOD and Series). The 1080 and 720 version typically don't. You don't like it, then you need to find a service which has what you want (I'm sure there will be nothing that is consistent on any service), or you buy a sub with some official streaming services.
Your useless long posts will not change much.
And even if you had external subs, you have no way of knowing which RIP you have, in order to be able to select the correct matching subs. 2 or 3 seconds to early or too late will ne just as useless anyhow.
If you want to do this, you can just download the VOD you want to watch onto your U5, then find multiple SRT files, dump them into the download directory, and then use VLC to play them.
Or you can learn a new language before watching the movie :)
Give the useless long posts a break.