I think this would be a really nice addition to the server. It would give players more ways to practice pvp, try out different kits and improve their strategies without having to make their own server or spend a lot of time getting everything they need.
I also think being able to test different pvp strategies is especially important for sections like Survival Explorer or OneBlock. The plugins in those sections can make pvp feel quite different from normal pvp, so being able to practice with the actual items, kits, and setups would help players see what works best in each section
Having things like custom kits, different armor, custom enchants, 1h pots, pets, talismans, and more would give players more options to try out. Overall, I think it would add more variety to the server, help players improve, and make practicing pvp a lot more enjoyable.