The 5100 series is going to be a tried and true upgrade over the base level suspension (Non Yellow HOSS dampers), and will give substantial ride handling improvements along with a decent boost to off-road terrain compliance. All that means is a sportier feel on the road, while being able to go a bit faster offroad in moderate terrains without the vehicle being bucked around as much.
We don't recommend going from the HOSS struts to the Bilstein 5100s. While you could do it technically if you need to replace the HOSS dampers and Ford is backordered (likely), you won't see improvement.
The 6100s are going to provide significantly more support both on and off-road. The 60mm piston provides almost 25% more damping surface area compared to the 5100 and HOSS pistons, requiring less work to remain stable under identical terrain. On-road feel may not change too much, except for small bump compliance (speed bumps shouldn’t be as jarring).
B8 6100 Typical Lift Heights with OEM Springs
Off-road performance is where the 6100s will excel, allowing the vehicle to travel even faster over identical terrain while maintaining traction and vehicle control. Those mini-whoops or rutted trails wont buck the vehicle as much since there’s significantly more rebound and compression damping to even out the peaks and valleys of suspension travel.