PoB: https://pastebin.com/1wf1xMKN

I also had HH on instead of Ryslatha's coil, which is another 20% DPS. There is still a lot to min-max with this build if you wanted to (have 0 elevated mods/3 prop jewels), but as you see there's just no reason to. If I were to invest further it would be to get additional fort effect on amulet/helm and more life. The build is also already extremely tanky despite having this much DPS, I have 110k EHP on PoB, which is quite a bit for a SC build.

The big difference between my lancing steel and other builds is stacking cluster jewels for extremely efficient dmg/hp, of course this is also more expensive but so worth it. On PoE ninja I couldn't find anyone doing the same and I do believe this is the best way to build a lancing steel champion, you could also go up to 7k hp if you put in 2 fettles, at the cost of 25%~ dps or so. That's what I would do for HC at least. (As I do believe this build is HC viable, just have to change a couple of things, but very expensive). You can also face tank any boss once you get any amount of life on hit, I have it on my watcher's eye, but not really needed because you just insta-kill everything anyway.

If you have any questions feel free to ask, while this build is very expensive, lancing steel champ can work on a budget, just get dreadbeak+saviour. Saviour is extremely cheap for being the best weapon in the game, it's honestly kinda busted.

EDIT: Forgot to mention that the build is also ailment immune, even though this is SC having that is just a huge QoL, you'll never die to a random shock or big ignite again. Also allows you to use 2 unique flask instead of 1, without having to sacrifice MS on your quicksilver. This is something I don't see many people go for, but it's something I would always recommend. It's also quite easy to achieve on this build.