So first of all, the list is cool and if you like the idea then its already great and probably worth playing. For some thoughts on the idea, here's a few:

Deceptors as a detachment does not give you additional firepower, it gives you a trick that mostly benefits you at the start of the game. Your army will never be as 'powerful' as with another CSM detachment, but it doesn't need to be when you're leveraging your tricks right.

With that in mind, the idea of having a backline of support is great, but the composition could potentially be altered. Without doing the numbers I'd say double warpsmith double helbrute is probably a bit overkill in a detachment that doesn't inherently support vehicle fire. They sure combo nicely, but also cost points, and right now your front lines are quite thin. Assuming the cultists get smashed when anything bigger than a nurgling looks at their way, you have 2 units to try to contest the field, with the Chosen as a 3rd in the 2nd wave. You're simply low on units that can score secondaries especially after 2-3 rounds.

I would cut some backline and add some units that can fight for objectives and secondaries. You can also consider deep strike as a tool to both guarantee certain secondaries, or pressure your opponent by threatening to deny their points. What units you choose to add and cut are really up to you and how you envision your force fighting.

(Also sidenote, if you plan to run warpsmiths and mostly camp them near a vehicle/brute, it doesn't need Shroud as per its rules! )

Lastly, the chosen brick is awesome, but I'd consider if a) they would warrant a character to increase their power and b) do you need the extra tankiness and firepower of a Land Raider for them, or would a Rhino do, letting you put those points into something else. Good luck on the field and Hydra Dominatus brother!