Custom dimensions cluelessness

Would anybody be able to help me resolve what is most likely a syntax error or dose of stupidity on my end for trying to generate a relatively simple custom dimension?
I think I've gotten the metadata pack format correct, I believe all the folders are properly layered. I think all the JSONs are valid. There's just somewhere where something isn't aligning as it should.
The datapack is recognized by the game, but in an error state that forces safemode to be enabled.