Need help with some problems!

Hello guys, yesterday i switched from vanilla to paper spigot for survival for 4 players. We have 2,5 gb of ram and stable 20tps. I edited spawn ranges to match vanilla. But i have some problems with paper. First one: Items are despawning after 5 minutes but if the chunk is unloaded the xp orbs are still there after 5 mins. Second one: When I am throwing out items they are sometimes invisible. I have turned off item merging. I started think if it wasnt better when i had vanilla. Can you please help me?

Items are despawning after 5 minutes but if the chunk is unloaded the xp orbs are still there after 5 mins

The first part is vanilla behavior. Items should despawn after being inside of a loaded chunk for 5 minutes. If the presence of experience orbs after this time is not vanilla behavior, you can report it as a bug on GitHub. I have personally experienced cases of items despawning in what seemed like less then five minutes, with experience orbs being let behind, but this appears to be a Mojang bug (MC-117783, which includes reports of this occuring on LAN-opened worlds and Realms) that can pop up anywhere.

When I am throwing out items they are sometimes invisible.

This one is not an issue I’m aware of. Do you have any plugins installed? I would guess not if you just moved to Paper. What version are you running (including build number, not just the Minecraft version)?

Paper-574. I have TabTPS and some plugin from my hosting service Hicoria MultiVIP. That cant be disabled. Also i have vanilla tweaks datapacks but i will switch to plugins. Btw minecraft version 1.16.5