This was mentioned in chat and I thought it’s worth saving here.
The HardROCK64 is built around the same six-core Rockchip RK3399 chip in the older RockPRO64 board (which also sits at the heart of the Pinebook Pro laptop). This offers 2 powerful ARM cortex A72 cores @ 2.0GHz, and 4 low-power ARM Cortex A53 cores @ 1.6GHz.
Similarly, the HardROCK64 comes with 802.11ac Wi-Fi , ethernet , Bluetooth 5 , and a microSD card slot as standard.
The version with 4 GB of RAM is $55.