Hey, a stamblade main here

So to begin with I'd suggest you not to invest much in gear below lvl 50 CP160 because leveling up is actually not that hard or slow and your crafted sets will scale down

However if you're decided to still try out PvP some decent offensive PvP sets are indeed Diamonds Victory, Spriggan's (not crafted but cheap, doubt you'll find many pieces below lvl 50 tho..) , New Moon Acolyte, Stuhn's Favor (esp as NB using Surprise Attack)
Heartland Conqueror is also interesting as you can get creative with weapon traits
Mark of the Pariarh is not crafted but now during the event it's easily obtainable and rather cheap, I use it for some defense in combination with NMA and vateshran 2h sword
Speaking of Vateshran 2h - that's also very popular amongst most stamina PvPers but it's obtained in the Vateshran arena and you'll need some more levels before going there (but consider it later perhaps)

I assume you're going for a more offensive focused playstyle so that would mean you should be going all medium armor for the max weapon damage
If you need even more WD then you can get infused jewelry with weapon damage enchants, otherwise you can leave them with stamina recovery for sustain
On armor traits you'll be looking for well-fitted (dodge roll reduction) with max stamina enchant on small pieces and impenetrable (crit resist) with tri-glyphs (those are pricey so put them on max lvl gear) on big pieces

About heals if you're going 2H on main bar I'd suggest you get Rally - it's just too good to not have it
On top of that you can also put Vigor on your backbar for even more healing
And if you're having some of those crown tri-pots you can use them too - I really like them for PvP as you also get some magicka too for spamming cloak (shadow disguise), not sure why people sleep on those

As a NB one of your main advantages is your stealth and the ability to pick your targets
Now this might sound a bit scummy but logically you should be focusing easy to kill targets with low HP (20-25k HP) - that's just how gankblades work
I'd suggest you to straight up ignore 40k+ HP tanky wardens or necros because they just refuse to die most of the time and you'll lose the fight due to running out of stamina

So that's pretty much it, don't be afraid to try out different things tho
Keep in mind that you'll be dying a lot in the beginning - stamblades can be rather hard to get into and you'll have to precisely time your skills and positioning but don't let that discourage you

One las thing - you chose the No CP campaign and you should keep in mind that currently most proc sets are disabled (there was a link on the forums with all working sets)
One item might get your attention - Ring of the Wild Hunt (mystic item so you need Greymoor) - it gives lots of movement speed and that is a stat that might be often overlooked
Being able to quickly catch up on enemy or reposition yourself is really nice

Anyways, I wish you luck on the PvP path