Problem 01
Subtitles
Personally, I like having subtitles on. Unfortunately the only way to make them play consistently across devices is to have them hard-burned directly into the video file itself - basically unremovable subs. This would also mean that I would have to re-encode every media I come across which is just absurd.
Solution
VLC Player — plays nearly any media file, and lets you pick a subtitle track on the fly instead of baking one in. You can download subtitles online, rename them as the same name as your media.mkv/media.mp4 file and activate them through VLC.
Problem 02
Casting
That only works locally — on the computer running VLC, or a mobile device running VLC. I tried casting VLC from a PC to the TV over the same network and ran into issues. Could be a TV software problem. Could be a VLC software problem. Either way, it didn't work.
Problem 03
Preparation
Tedious to set up. You'd have to copy the file into VLC every single time — it isn't readily available. Even with the movie sitting on a cloud drive, you'd still have to import it into VLC, per device, every time you wanted to watch it.
Problem 04
Franchises Fragmented
I always wanted to have a day to binge the Marvel Endgame series. Unfortunately, when I had the free time it was difficult to find a good stream with good quality without intrusive ads. I mean, that is just the way it works if you want something for free.
Anyways, other than finding a good source — I wouldn't even know what order to watch it in and I'd have to go through another ad infested navigation phase to the next movie. There was a time where I did subscribe to Netflix just to see they only have one part of a franchise, and HBO MAX having the other movie, etc.
Poop. So to get the true experience I would have to pay subscription for multiple streaming services when to watch 1 days content. There have been months where I just pay these streaming services after I watched the show I wanted to and just leave the subscription idle. I'm pretty much done with that.
So — if I had a movie on my PC, how do I play it on my TV, with the option to use subtitles?
Found it
This is when I discovered Plex.
One server, multiple libraries, subtitles included — playable on anything in the house without the copy-paste routine. Next: getting it installed, and figuring out what hardware should actually run it.