Replace NX Eagle derailleur with SX or GX?

Hi all

First post here, so nice to meet everyone.

I have a damaged NX Eagle derailleur that needs replacing. Turns out there are stock issues everywhere until October. So I wonder if it's an issue downgrading to an SX eagle derailleur, or whether it's worth upgrading to GX. Considering cost, obviously, and I understand the GX would require a new XD driver if I were to change the cassette at the same time.

So is it pointless downgrading? I'm not doing more than 40k a week. If I upgraded could I stick with the 11-50t cassette and NX shifter? Appreciate that'll probably make the derailleur less functional than it should be.

Cheers