Shuffle not random enough

As the title says, I have the Clip Sport Go after trying numerous MP3 players to replace my venerable (and still AMAZING) Creative Zen Mosaic. How is it that modern MP3 players still can’t tick all the boxes of what makes a great MP3 player these days ? The only reason I had to upgrade is because of storage size.
I’ve tried numerous and they all fall short in one way or another. I use it to listen to music in the work van when I’m out on deliveries. Battery life is good, sound is obviously important, but what I really want is a shuffle that ACTUALLY shuffles ! That’s all I listen to, and all I want - I don’t care about playlists, I just want shuffle.
I heard such good reviews of the CSG, that I went for this after returning about 5 of the other unsatisfactory players from a certain online store.
So, when I have 32GB of music, why does this device regularly play the same songs ? How is the random shuffle algorithm generated ? I have shuffle selected from the root of the music directory, and it DOES play a good mix, but it’s about 50/50 - half are random songs from the whole device, and half are repeated within a pool of the same favourite songs, sometimes twice within a span of 5 songs.
Can someone please explain, or better yet, investigate the science behind it, and fix it ?
Thank you