Sorry for bumping an older thread. I am running the 23.05 openwrt that I compiled myself (same result with snapshot) on WR1300 V3
However my 5G wifi would only allow up to 3dbm tx, which is pretty bad.
iwinfo phy1-ap0 txpowerlist
0 dBm ( 1 mW)
1 dBm ( 1 mW)
2 dBm ( 1 mW)
* 3 dBm ( 1 mW)
and:
iwinfo phy1-ap0 info
phy1-ap0 ESSID: "openwrt-5"
Access Point: F4:A4:54:85:C4:CC
Mode: Master Channel: 40 (5.200 GHz) HT Mode: VHT80
Center Channel 1: 42 2: unknown
Tx-Power: 3 dBm Link Quality: unknown/70
Signal: unknown Noise: -90 dBm
Bit Rate: unknown
Encryption: mixed WPA/WPA2 PSK (CCMP)
Type: nl80211 HW Mode(s): 802.11ac/b/g/n
Hardware: 14C3:7663 14C3:7663 [MediaTek MT7613BE]
TX power offset: none
Frequency offset: none
Supports VAPs: yes PHY name: phy1
Am I doing something wrong? I am running out of ideas, which is why I decided to come here and ask around as to what might be wrong with this picture 
It works fine when im right next to it, but if I go in a different room - that baby is slowing itself down significantly.
Thank you for any help or advice you can provide!