I’m trying to figure this out visually so it’s easier to understand.

Breeding pair A and B produce children C and D. They cannot breed without degeneration, so I breed them to E and G, respectively.

Pair E and C produce F, pair D and G produce H. F and H cannot breed with degeneration, so I breed them to I and K respectively.

Pair F and I produce J, pair H and K produce L.

Can I breed J and L without degeneration?

Yes!

Usually the way I check is go to the mother/father's tab. Look at their parents.

If there are no common parents or grandparents, it's a go. I used it to breed some of my Raider symurgh (no degen) from my very first male Raider.

OG Raider had a female kid I'll call Dreams, and Dreams had some kids. Then those kids bred with an unrelated symurgh, and Dreams' grandkids can successfully breed with my original Raider despite them being related. It just has to be far along enough.

That’s the answer I was hoping for, thank you!