The first version of ESP32-C3 super mini has a broken antenna design. The workaround is after WiFi.begin reducing the Tx-Power to reduce reflections.
WiFi.begin(ssid, password);
WiFi.setTxPower(WIFI_POWER_8_5dBm);
Then I saw in
http://esp32.io/viewtopic.php?f=19&t=42069
the pin 21 issue.
I soldered out the single row male pin 21 and removed
WiFi.setTxPower(WIFI_POWER_8_5dBm);
again and it connected every time.