Would a steroid shot help for pollybeak from a revision rhinoplasty?

I agree with the others, such that you have nothing to lose by trying.  Two years after a revision surgery the nasal structure is probably fairly established, but your only other alternative is a second revision surgery to remove what would then be clearly established as dorsal cartilaginous septum.  You would know within a month, so you are hardly delaying further treatment if you just give it a try.

I read your concern. If your bridge is too high such that you have a "polly beak", Revision Rhinoplasty may be necessary to improve the appearance of your nose. Posting a profile photo would help us advise you.

Steroid injections are useful in reducing post-op swelling usually within the first year after your rhinoplasty Surgery.

Regards from NJ.

Having an injection of either a steroid or 5-FU to combat excessive scar tissue is a possibility, although it may not help very much if there's a large residual cartilage component.

Examining your nose in person would allow for a better assessment of your chances of improvement with an injection. Residual cartilage would have to be surgically removed to improve that aspect.