The difference between the 5438 and 5400 ESP32 Feather boards from Adafruit Industries LLC is the antenna.
The 5400 uses a PCB trace antenna, but the 5438 has a w.FL connector for connecting an external antenna.
Available antennas with w.FL connection:
RF Antennas | Electronic Components Distributor DigiKey
If you already have an antenna you can see if we have an adapter so you can use the antenna you already have with the w.FL connection on the 5438.
Coaxial Cables (RF) | Electronic Components Distributor DigiKey
SMA to W.FL Coaxial Connector (RF) Adapters | Coaxial Connectors (RF) | Electronic Components Distributor DigiKey