There are several reasons why I don't think Didl is Josh's GF.
1. Didl draws too much attention to themselves
2. Didl has caused endless conflict since they arrived.
3. Josh is not any happier and in fact he seems to be on the verge of a depressive meltdown
4. Josh has been talking a lot lately about his fake whataburger GF. Like almost every stream, if you look at the archive comments almost every one has "whataburger mention" in the comments. He's trying to meme this since around the time rekieta started calling him a kissless virgin with no social skills. I think youthful shannel is correct on this.
5. Didl's account was inactive for a long time before use leading to a high possibility of a sock regardless of who is operating it.
You might say that this is explained by Didl being a BPD Yoko Ono psycho, but then why is Josh mentioning his "ex" so often? BPD psychos don't like that so much.