If you have a trinket equipped (Such as something from Botania), and have player death items set to never despawn, they will still follow the default despawn time and disappear after 5 minutes.
I ran a test over 5 minutes to see what happened, and this is what was left after that:
After setup:

After 5 minutes:

On the left are items I dropped manually with Q, on the right are items I had on me when I died.
I had the blue band in a trinket slot.

I am on Fabric 1.20.1, tested with Botania trinkets.