Now that AMD officially announced the top-of-the-line Navi 21 GPUs, there is no reason to restrict AIBs from designing custom RX 6900 XT versions anymore. Industry insiders are hearing that AMD is already in talks with its partners to release such custom flagship cards, and availability could be set to early 2021.
https://www.notebookcheck.net/AMD-may-allow-AIB-partners-to-release-custom-RX-6900-XT-cards-soon.500821.0.html