ViaBackwards VS Purpur

then you should use ViaBackwards in combination with ViaVersion.

You may want to try submitting a bug report here

Also, consider using one of the Paper forks that includes further performance improvements. For 1.18.2 two options are Pufferfish and Purpur. Pufferfish has a lot of optimizations, but now Purpur actually downstreams Pufferfish too so it includes all of its improvements (plus a ton of other features which are optional and turned off by default). Purpur as far as I can tell is currently the most complete Paper fork, the only downside in my opinion is that they only support the latest versions of Minecraft. Previous Purpur versions have not been patched for Log4Shell. Since you are running 1.18.2, this shouldn't be a problem, but keep this in mind for the future - if using Purpur you'll want to update soon after a new server version releases to continue getting support, or switch to another Paper fork (which shouldn't be a problem as long as you don't use any of the optional Purpur features). I personally prefer just using the latest version anyway though, and then I use ViaVersion plus ViaBackwards to support older clients.

Probably not your issue, but just because I heard of it, there's an issue with the inventory desyncing if using ViaBackwards.

We will be downloading the Minecraft server files into this directory. To preface, there are numerous variations of server JARs that can be used (e.g. Spigot, Paper, Purpur each touting their own benefits). For this tutorial, we will be working with Paper, a fork of Spigot that is optimized for performance.

I Mostly Like Linux as a OS For a Server and PurpurMC (https://purpurmc.org) As a Server Software and i Mostly Use EssentialsX and WorldEdit and More Server Management Stuff.

If you prefer to go the old-school Bukkit/Spigot/Paper/Purpur route (which provides the greatest level of compatibility with pre-existing server plugins), I recommend the latter of the four. Each of these projects is a fork, built on each other in that same order. Each fork offers additional customisation, API, and performance enhancements over its predecessor.

I’d recommend Paper (which is a fork of spigot) or Purpur which is a fork of paper and pufferfish

If you're looking to re-add gravity duping I would recommend not using a plugin but switching your server software to PurpurMC. It is a fork/version of PaperMC that re-adds gravity duping as a config option as well as the ability to toggle back on things like tnt duping and several other features that the PaperMC devs arbitrarily decided were bugs (even though Mojang has explicitly not removed them).

Small addendum:\ If you want to keep using a paper derivative (as a drop-in replacement), you can use purpurMC instead. It provides a config option to enable gravity block duping by disabling sand.fix-duping. (At least for sand)

You can host a small purpur server

Have you tried re-downloading the latest purpur jar file from the purpur website?

tweak some configuration, try lower your entities spawn, I at last you might want to try PurPurMC for the server, it's paper fork with some modification, I feel a lot of improvement since using this fork...