Firestick 4K Max - Major Issues

[Fran314]

compare to a copy of the 1080p video in the new log without pgs subs, ffmpeg -i (infile) -map 0:v -map 0:a -c copy (outfile).mkv

This actually played flawlessly, so I'm guessing it was all about the subtitles type. Any possible fix for that (maybe by not allowing subtitles extraction on the fly in the playback settings)? Or should I just avoid pgs subs?
I don't think the log for this playback is of any help but if it is I'll share it. Looking at the playback information from the dashboard, it said that the playback wasn't on direct play but on remuxing, claiming that the streams were compatible with the device but the container wasn't so it is repackaging it on the fly. Is this expected behaviour?

What are your server specs?

OS: Arch Linux x86_64
Kernel: 6.6.3-arch1-1
CPU: Intel Pentium Silver J5040 (4) @ 3.200GHz
GPU: Intel GeminiLake [UHD Graphics 605]
Memory: 8GB

Again thank you for your help! I'm still a bit confused on how to properly quote other messages by other people so the post is probably badly formatted, but this is another issue for another time