That's how backups work, it saves your IP, software, version, etc.
If you want to change your software from Forge to Spigot, you have to download the world, then switch the software, and upload the world.
Thanks, but when so tried downloading, switching to spigot, and then redone loading the world through a backup it still made it forge. Or is there some other way to download the world that I don’t know about? And if so does it save players items, XP, and progress? Sorry for the all the questions I am just very confused and we have spent a lot of time on the sever!