it may not make sense to comment on the layout without actually looking at it. but if there is a layer of ground between the chip and battery, that may mitigate to some extent. the chip antenna supplier will often provide some layout guidelines based on their products.
in the case of use of BCM20737S, the antenna is embedded on the chip. the refdesign put the coincell battery in side of the rf circuit. is that necesseray ?
It's my understanding that the placement of the battery is not an intergral part of the RF design. More immportant items include the location of the connection to system ground, size of the keep out area and the shape of the ground plane that is used for the embedded BLE antenna.
Guidelines for the optimal PCB design are described in the PCB/Layout section of the CYW20737S Bluetooth Low Energy SiP Module Technical Reference