Cannot play directory or playlist using kodi-send

I’m trying to play a list of .mp4 videos upon startup in /storage/.kodi/userdata/autostart.sh

Based on this documentation: https://kodi.wiki/view/List_of_built-in_functions#Profile_built-in’s

Playing directory contents should be possible, eg kodi-send --action="PlayMedia(my_dirname, isdir)" but from the log it appears to be treating it as a file:

2025-01-07 05:52:57.400 T:3701     info <general>: VideoPlayer::OpenFile: /storage/kinectproject/
2025-01-07 05:52:57.410 T:6240     info <general>: Creating InputStream
2025-01-07 05:52:57.411 T:6240     info <general>: Creating Demuxer
2025-01-07 05:52:57.411 T:6240  warning <general>: underflow: Error reading file - assuming eof
2025-01-07 05:52:57.411 T:6240     info <general>: Skipped 1 duplicate messages..
2025-01-07 05:52:57.411 T:6240    error <general>: Open - error probing input format, /storage/kinectproject/
2025-01-07 05:52:57.412 T:6240    error <general>: OpenDemuxStream - Error creating demuxer
2025-01-07 05:52:57.412 T:6240     info <general>: CVideoPlayer::OnExit()
2025-01-07 05:52:57.464 T:3701     info <general>: GLES: Maximum texture width: 4096
2025-01-07 05:52:57.465 T:3701     info <general>: CVideoPlayer::CloseFile()

I saw in this topic that it seems to be broken: Autoexec.py on Nexus? - #2 by vpeter

so I tried creating an m3u playlist instead, however I’m getting errors there too:

2025-01-07 06:36:41.299 T:6900    error <general>: GetItemsForPlaylist failed to load playlist /storage/kinectproject/playlist.m3u
2025-01-07 06:36:41.302 T:3701    error <general>: Playlist Player: skipping unplayable item: 0, path [/storage/kinectproject/playlist.m3u]
2025-01-07 06:36:41.307 T:3701     info <general>: GLES: Maximum texture width: 4096
2025-01-07 06:37:42.341 T:3730     info <general>: ES: Client  from 127.0.0.1 timed out

The contents of the m3u file are:

$ cat /storage/kinectproject/playlist.m3u
#EXTM3U
/storage/kinectproject/myvideo.mp4

Are there any alternatives to play a list of videos on startup?