Hi @BenSud
if you need to use only single antenna it is better to use the DW3210 as the DW3220 contains internal RF switch which introduce a small attenuation so you will have a slightly worse reception.
Regarding the unused RF2 port - it is highly recommended to Ground the unused RF port via the 50R resistor as there is some small cross talk across the RF ports. However even without the 50R it should work OK.
Cheers
JK