Build advice
Berserker gear is the thing in pve.
Survival stats to comfort is the normal path of a thief in wvwvw. If you want to do it all I’d recommend at least the main armor as berserker. If you want some more survivability in wvw throw in some cavalier, soldier(both karma purchasable), valkyrie, or knights trinkets.
In spvp the berserker amulet is all you’ll need.
Berserker weapons, at least one of each you can use. Two if you like those setups (dd, pp), or you need additional sigil options(shortbow).
Buildwise 66002 or 560(30 or 03) for pve.
some fun spreads to first get comfortable in wvw are 26600, 06620, 20606 for dagger mainhands(usually) and 20066, x606x for swords. Some people come off SA Traits once they are more comfortable. Some keep them. All preference.
Good luck and I hope this is beneficial to your journey.
Also these are my opinions and I’m a scrub with a little under 2k hours between my thieves.