How to make WiFi reduced transmit power level persist across reboots?

**TL;DR** I have reduced the transmit power of a WiFi device and I would like to make this change permanent, so it does not revert after a reboot. **Details** I have joined two Raspberry Pi 4 devices to an existing WiFi network, and I have discovered that by default they transmit at 31 dBm, which is quite high. I was getting a lot of latency, in that it would work fine for 10 seconds and then pretty much stop for 5 seconds, then repeat. I discovered that if I lower the transmit power on both devices to only 10 dBm then the latency dramatically improves. I did this by running the command iw wlan0 set txpower limit 1000. I would like to make this setting persistent across reboots, however I can't see anything in systemd-networkd or wpa_supplicant that controls transmit power. Is there a way to set this (e.g. in systemd's .network or .link file for the WiFi connection)? Failing that, what would be the best way to do this? I am guessing a udev rule would be better than a systemd service as it would run only when the device is available however any advice would be appreciated.