Reload

If the server is running on the Spigot platform or its fork (Paper, Pufferfish, Purpur, …), do not use the reload command, especially if it is a production server. You can learn more why here.

Using the Vanilla reload command to reload datapacks is fine. You can do this by executing the minecraft:reload command instead of reload.

Reloading plugins

As with the reload command, don’t use plugins such as PlugManX to reload other plugins (you can learn why in the article mentioned above)! When installing/removing a plugin, restart the server.

If you want to reload the plugin to apply configuration changes, use the reload command of the plugin if the plugin has such command (e.g. EssentialsX has ess reload). Using reload command of the plugin is perfectly fine. If the plugin has such command, you can find it in the plugin’s documentation. If the plugin does not have the reload command, restart the server.