ASUS' RT-AX58U AX3000 Dual Band WiFi 6 Router has been tested and added to SmallNetBuilder's Wi-Fi Router Charts. Also known as the RT-AX3000 and RT-AX82U, its Broadcom-based design is spec'd for two streams on 2.4 and 5 GHz. However, since the 5 GHz radio is Broadcom's BCM43684 four stream an/ac/ax radio, it appears it support four-stream receive under the hood.
The router didn't do that well in our throughput vs. attenuation tests, however, due to sustained throughput dips on both bands' downlink tests that were observed on multiple test runs. Check the Wi-Fi Router Charts for more details. There is no full review of this product at this time.