Hello everyone
This is my first time creating a build on PoB. It may be not perfect for now, as it serves the theory for now to me, so I do have some questions on build creation and the use of PoB.

But first here is the idea I'd like to realize :

Move from pack to pack with Withering Step then Ambush to crit with Frost Blade, using the projectiles to clear the packs.
For bosses, I hope to have enough DPS from high attack speed and crits.
As for defences, I aim high evasion rate with, obviously, a decent amount of life and maxed out resistances and spell suppression.

Questions that I have :

• On PoB, my DPS is lower than I thought it would be with almost 10x crit multiplier. How could i have more damage output ?
• If I'm not mistaken, the projectiles coming from would have the damage of the initial attack. Does that mean that the crit damage is applied ?
  Considering that the projectiles also return (support gem) does that mean that the damage is applied 1 (the attack) + 7 (number of projectiles) + 7 (projectiles returning to me) = 15 time ? Does PoB calculate all that ?
• Are all the items selected a good choice ? And is it achievable in term of craft or (more preferably for now as I'm still a noob ) buying ?
• I'm not sure I did well with the configuration tab tho.
• Do you have any tips or recommendation for the build or in general ?

Here is the link to the PoB :

https://pobb.in/ntxxIpw6FDW6

For context, this is not my first character, I have almost 400 hours in and played several characters, mostly using guides, other times trying to build instinctively (and failing at it most of the time lol), doing red maps and bossing (exarch, eater, maven) at most.
I do have a character in this league with some currency banked in.

Thanks a lot, you kind community !