If you are facing poor Wifi capabilities (e.g. slow to dish out IP addresses via DHCP in AP mode or unreliable connection in STA mode) with your SparkFun ESP32 Thing, it might be that there is an easy fix:
Solder on capacitor C28 (2.4pF)
This goes on the top where the antenna is located (see schematic middle left part).
Please note, while C8 (5.6pF) is equipped, L1 (2.7nH) is also missing but its not required per se.
This tip was made on the SparkFun forums, and reportedly also 5.6pF worked.
The reported RSSI increased from around -90 to -65 in STA mode while at the exact same place.
No clue why SparkFun did not equip the parts in the first place, or use ready made ESP32 SoC with the Wifi parts.