A very simple to use Plugin.
Command:
/losspercentset [percent]
Make sure to write it without the % symbol, only the number you want.
and boom, everytime you die, the chance you specified will be run on each item. Making you keep about half of your items on death, and losing the rest
RandomItemLoss is a free Minecraft Java mod. Compatible with Minecraft 1.21. Downloaded 92 times (via Spigot). Download it and open it directly in the game.