Not sure if you are looking for a Mopar cover or an aftermarket. I just put on a BAKFlip MX4 cover this weekend on my 2019 Big Horn with RAM Boxes and I am very happy with the looks and operation.
Works well with the RAM Box covers. The MX4 is very low profile, so I can open the covers fully. Moderate rain yesterday, and just a few drops of water inside under the gap between the tailgate and bed wall (not the fault of the cover). Off to Lowes at lunch to find some 1" foam seal to cure the gap.
If interested, shop around, but I got a very good price from our Site Sponsor, Tonneau Factory Outlet.