Worth noting that WiFi 5 is 802.11ac, which only applies to 5Ghz; any WiFi 5 gear is using 802.11n for 2.4GHz. (Edit: Pi 4 can do 5GHz) One wonders if they skipped doing a 5GHz antenna for cost/space/other reasons.
[1]: https://www.seeedstudio.com/Raspberry-Pi-Compute-Module-CM41...