I have multiple video series in different folders.
Need a video player with tracking feature - remember which video last played.
Almost got it : the great VLC has it. https://www.vlchelp.com/grouping-listing-video-orientation-android/
Still, I am looking for other apps…
NPlayer is really good in my experience. It works with the vast majority of files. It sometimes struggles, but anytime that happens VLC picks up the slack. It remembers where you left off in individual video files. It’s not on Fdroid, sorry about that, but there are Android and iOS versions.