Yeah, to be honest, I am not a fan of chip antenna types. They are fine for testing on the bench and ‘short’ range applications. Take note of the KH5220-A36 datasheet, specifically the test PCB, specifically the size and distance (or rather lack of nearby components).
Most antennae datasheets provide ‘keep away’ zones of all metallic components to avoid interference losses. In the case of the XIAO ESP32C6, the antenna is located quite close to the metal shield casing; difficult, if not impossible to avoid when designing small devices. Fortunately, the external RF port is a good alternative with a suitable antenna. The RF switch is very useful as most other dev boards require a jumper resistor be to be resoldered to a different position which can be tricky and time consuming. This does come at a cost of extra energy consumption and losses but can be negligible depending on your use case.
It is also possible to adjust the RF TX power, this doesn’t help with RX sensitivity of the ESP, but can be useful provided that you don’t break any rules regarding transmit power/gain when including the antenna type, etc.