broadcom – Ubuntu 20.04 + Macbook 12 + BCM4350 [14e4:43a3] (rev 05) = slow wifi 5Ghz?

Ubuntu Wifi 5GHz speed 6 MB/s

Macbook Wifi 5Ghz speed 37 MB/s

Ubuntu

ssh asus 'dd if=/dev/zero bs=1048576 count=1024 2>/dev/null' | dd of=/dev/null
2033542+65124 records in
2097152+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 174.749 s, 6.1 MB/s

Macbook

sh asus 'dd if=/dev/zero bs=1048576 count=1024 2>/dev/null' | dd of=/dev/null
2037403+60915 records in
2097152+0 records out
1073741824 bytes transferred in 34.550463 secs (31077494 bytes/sec)

Hardware

02:00.0 Network controller (0280): Broadcom Inc. and subsidiaries BCM4350 802.11ac Wireless Network Adapter (14e4:43a3) (rev 05)
    Subsystem: Apple Inc. BCM4350 802.11ac Wireless Network Adapter (106b:0168)
    Kernel driver in use: brcmfmac
    Kernel modules: brcmfmac

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