Hello DevilishDreams,
You need 1 netherite ingot and 1 smithing template to convert any diamond item into netherite. When you open smithing table, you will find three places. Place smithing template on the first place, diamond item in second place and netherite ingot on the third place.
In op lifesteal there are many custom enchants. That swords may contain those. Do /ce to take a look over them. there are two types of custom enchants-refined and archane. refined custom enchants can be obtained from villagers and archane enchants can be obtained from archanist orb which you can get from /enchanter. There are many custom enchants thats why swords have many enchants.
BTW i know reading this much will be boring XD.