Remuxing a TS file to MP4 results in a less fluid video
There's lots of Invalid timestamps and Invalid DTS errors, but I'm not sure they're related to the problem.

They are, frames in video streams with B-frames are not encoded or stored in presentation order, so the presentation timestamps have to be correctly offset for fluid playback. In this TS sample, you have presentation timestamps earlier than decoding timestamps, which are invalid, and ffmpeg defaults to assigning the DTS as the new PTS.

Instead, use existing PTS as the reference.

ffmpeg -fflags +igndts -i all.ts -c copy all.mp4