You can access the level.dat, tho not directly in Aternos. You can download your world, edit level.dat, then upload only level.dat again
Good info! thanks! However, I have some fun news! By putting it into vanilla and setting everything to easy (and not peaceful) in vanilla, and then reinstalling spigot, the bug is fixed! Based on this conversation, https://www.spigotmc.org/threa…ifficulty-setting.451984/ I discovered that for whatever reason Spigot has issues changing the difficulty of anywhere other than the overworld, but if you generate a new world spigot is just happy to use that new world's difficulty. I figured I'd give it a shot setting the world difficulty in vanilla, where I know it works, and then handing the world off the spigot, and it worked! I think if I want to change the difficulty of a dimension reliably, I'll have to do it in vanilla, for the time being. Thanks for all your help Roman and Toothy