Also, if you are patient enough, you can send in their sheds to test if they are male or female…
Genetic Testing Now Available!
As for soft fur rats, if you can get them, you could try that. I know that where I live they’re almost impossible to get except at nearby reptile shows.
This is a little much but maybe you could try a 28qt plastic bin with a hide to see if s/he feels more comfortable eating in a smaller enclosure. Probably overkill though. And feeding a live mouse? Just throwing out some ideas I’ve read about on here.
And welcome to our awesome community!