I use a file browser that also plays audio and video: Total Commander
It “remembers” recent playlist and play point of the file, as long as I don’t click the red ‘X’ in the controls.
It’s not on F-droid, but it’s possible to add its repository to F-droid.
Oh yes, do not do that! I certainly didn’t do it. And I’m gonna not do it again if I need to.