The current limit is 128 files per directory.
You can change your current directory when you are looking at a game list by tapping the folder icon in the bottom left corner.
I do believe after searching for a while that the is no final English version of DSM converter. Though Chinese one was released in summer.
In my experience with this converter DSM movies are by far inferior compared to DPG.
For everyone who desires movies on M3 Real a much better option would...
btw i feel this a good time to remind you guys that sea of thieves was made by rare, who also made DKC1-3 and DK64, alongside banjo kazooie and conker's bad fur day