You asked for a recommendation. Shocks are a pandora's box, everyone has their favorites and reasons why.
I have remote res Fox's, Bilstein yellow's and the rebuildable racing/7100's, Old Man Emu nitrochargers etc. Jumping from truck to truck they all give different ride quality/characteristics
Yes you need longer shocks. I have 764's on the front of 4-5 trucks here and that spring requires a longer shock up front. I have used bilsteins but the ride is stiffer than is ideal. If you want Bilsteins order the ones for the front of a RRC LWB- they have two inch longer travel to work with the EAS. For me, the OME's have given a better ride quality. Fox makes a nice shock, but make several grades. My Fox's 2.0's are with Fox being rebuilt/serviced @ present. Someone had posted that there are availability issues with Bilstein presently. Ride quality is all about valving. Cant speak to the Koni's. Tried them on BMW's back in the autocross days and they were very stiff shocks. No idea how they are valved for Defenders. I have a pair of long (26 inch front) Bilstein 7100's sitting here with
170/60 valving which is very, very soft.
What you dont want is that a shock be fully extended @ rest. Ie if you have to ratchet strap or otherwise compress the suspension to get the nuts on the bottom of the shocks, ride quality will suck, and suspension will make banging noises.
The shock should be partially compressed @ rest.