Just wanted to make sure I wasn't doing something stupid but I think you're right! Appreciate you commenting.

I ended up using 6 screws on a 2x4 since I didn't have a great space to fit a 2x6. Seems solid I'll let you know if it falls down 😂

Thank you. I'd rather over engineer it than the other way around and have it fall down and rip the electrical connections apart!

Thanks for the input. I think that would put me in the same position as I'd have to extend the box downwards, which I can do with the current box I have. Neither HD nor Lowe's carry an extension in store.

It's also not new work and maybe I could get that type of box in with an extension bit. But it doesn't solve my issue as far as I can tell.