Actual sharpening doesn't take much time and removes very little metal. The hardest part isn't actually sharpening, it's
shaping the edge. Often the edge will be thick, uneven, or simply in need of metal removed.
This video shows the basic technique:
https://www.youtube.com/watch?v=OPGGo3W15HQ
If you're using hand tools, stones, ceramics, diamonds, silicon carbide wet/dry sandpaper, etc. it might take a while to shape (thin down) the edge to where you reach the apex on both sides at the same (or close to the same) angle.
Most likely the BK14 you purchased wasn't ground evenly so the tip/belly portion of the blade is thicker or at a higher angle than the rear portion. That means you have to keep at it and remove more metal until you thin it down enough to where you are hitting the apex.
You can do this free hand, on a jig system, or you can simply send it off to someone to thin down the edge. Once you are able to reach the apex at, say, 15 degrees per side, maintenance is a breeze and will only take a few swipes at an angle higher than 15 dps to actually
sharpen the knife.
I hope this makes sense. Even a "lowly" carbon steel can take a while to shape if you have to remove a good bit of metal.