Who's "they're"? AMD never said that. That came from sweclockers.I believe facts, you should also.
^This is from 5700 line of cards...
"AMD Radeon RX 5700 Series With First Gen Navi Have a Hybrid RDNA and GCN Architecture, Next-Gen Navi ’20’ To Be Pure RDNA Based"
They're calling their GCN hybrid RDNA, they're trying to mask it but that's exactly what it is, it's still GCN.