I am running a Minecraft 1.16.1 server with spigot and bukkit, I wanted to know if items despawn in minecraft servers, if they do, how much time is there, can you change it or stop it. Also if there is a way to find the coords of the last death of a player in a Minecraft server.
Yes, the same rules apply as to single-player: items in entity-processing loaded chunks (be it within load distance from a player, spawn chunks, or permaloaded by portals or /forceload) despawn after 5 minutes. Items in unloaded and lazy chunks have their despawn timer frozen.
The significant, if obvious differences are that player's client render distance doesn't affect the player chunk-loading radius - the view-distance property in server.properties does. The server (and all its associated timers) doesn't pause when a player goes to inventory or esc menu (duh), and spawn chunks don't unload when no-one's playing.
item-despawn-rate property in spigot.yml where the despawn time is given in gameticks, 6000 (5 mins) by default.