Cool, I’m not overly familiar with A7X, aside from their Rock Band and Rocksmith appearances, so can’t really recommend anything there (Afterlife is good fun). You can’t go wrong with Metallica, they have something for every skill level, Bellz is pretty quick and easy to learn, Sanitarium for something a little more challenging or just about anything from the Black album should fit your criteria.
Panteras Mouth For War (or Walk?) is fairly straight forward and good fun to play. System of a Down? Hypnotize, Aerials may be a couple of options. Slayers Dead Skin Mask, Machine Head Davidian, Old or Death Church may suit.
To be honest there are sooo many options we could potentally list hundreds. Best bet is to pick a song you really like that sounds like it fits your skill level and start working on it piece by piece.
Maybe post a few vids as you learn each section for some helpful critique?
Disclaimer: Im a 40 something year old rhythm player, so my selections don’t take solos into consideration.