Ok. My phone LG G6 and my laptop was tested on original firmware.
Original firmware:
WLAN <> LAN = 79 Mb/s on 2,4Ghz - laptop and phone LG G6
WLAN <> LAN = 335 Mb/s on 5Ghz - laptop and phone LG G6
Openwrt:
WLAN <> LAN = 53 Mb/s on 2,4Ghz - laptop and phone LG G6
WLAN <> LAN = 105 Mb/s on 5Ghz - laptop and phone LG G6
So my PC hardware is not a bottleneck.
My /etc/config/wireless
root@OpenWrt:~# cat /etc/config/wireless
config wifi-device 'radio0'
option type 'mac80211'
option hwmode '11g'
option path 'pci0000:00/0000:00:01.0/0000:02:00.0'
option country '00'
option legacy_rates '1'
option htmode 'HT40'
option channel '6'
config wifi-iface 'default_radio0'
option device 'radio0'
option network 'lan'
option mode 'ap'
option ssid 'Openwrt_2G'
option encryption 'psk2'
option key '...........'
config wifi-device 'radio1'
option type 'mac80211'
option channel '36'
option hwmode '11a'
option path 'pci0000:00/0000:00:00.0/0000:01:00.0'
option htmode 'VHT80'
option country '00'
option legacy_rates '1'
config wifi-iface 'default_radio1'
option device 'radio1'
option network 'lan'
option mode 'ap'
option ssid 'Openwrt'
option encryption 'psk2'
option key '..........'