unfortunate issue when transferring Minecraft worlds

I have Server.jar 1.16.4 Minecraft server software set up and ready to go, and I want to transfer a world and all contents from the Minecraft world directory to the server.jar world directory. This worked, but my hot-bar and inventory have been cleared and my XP value has been reset back to 0 (previously I was at level 130+).

I would like to keep this as it was in the original world, but have the world running on the server. Is it possible to do such a thing, or must I put all my items in a chest and regain all my levels?