"I was told Rockchip no longer considers RK3588 to be an “open source” chip. In practice, that means Rockchip no longer contributes RK3588 code to open-source projects and they also decided not to sell RK3588 directly to SBC vendors." https://www.cnx-software.com/2024/12/21/rockchip-rk3588-mainline-linux-support-current-status-and-future-work-for-2025/
This, paired with Joshua Riek stepping away from ubuntu-rockchip, doesn't bode well for RK3588's SBC futures.
Maybe why Radxa is going with a different vendor for their next flagship board, the Orion 6?