Extra Step: Custom Enchantments Plugin Compatibility

EcoEnchants

If you want to hide enchantment description lore provided by EcoEnchants, you have to:

For ProtolcolLib: Default config should be enough for you, do not need change anything. EnchantmentSlots will try auto hide enchantments, but if it is not work, do the same thing below.
For eco: If you set use-listener-plugin option to eco, you must disable display.enabled option in EcoEnchants's config.yml.
eco is not recommend use unless you want to specify the location of the Lore added by EnchantmentSlots when editing items simultaneously in plugins such as EcoItems, Reforges, and EcoEnchants.

If you want to hide enchantment description lore provided by ExcellentEnchants, you have to:

Change ExcellentEnchantments's config.yml Display.Mode option value from 1 to 2.
Keep use-listener-plugin option to ProtocolLib as this plugin is also trying use this plugin.
Keep packet-listener-priority option to LOWEST, do not change it to other value, othervise ExcellentEnchants will still try display it's enchantment description.

The best way is check if the custom enchantment plugin has this feature.
If the custom enchantment plugin doesn't has, you can use enable set-slot-trigger.add-hide-enchant-flag option in config.yml. After enable, EnchantmentSlots will auto add HIDE ENCHANTS flag to the item new generated in player inventory. Existed item can be converted by click it in player inventory.
Sometimes change packet-listener-priority option maybe work if the enchantment plugin is also packet based.
If this still does not work for you, then you have to ask cutom enchantment author add this feature for you, EnchantmentSlots can do nothing for this.