Need help understanding surprise/invisibility + ideal dual wield assassin 3 multiclass build.

TLDR: I’m trying to make a dual wield Astarion assassin (Rogue Assassin 3 is a must) build that gets as many guaranteed crits or the biggest numbers as possible from stealth/resets using items such as the DU cloak and the Assassin 3 passive for as much melee burst damage as possible. I have already played dual wield hand crossbows and don’t want to do it again.

I’ve been trying to build a dual-wield assassin character for a while, but I’ve just reached act 3 at lvl 9 and it feels like it hasn’t clicked yet (I know it’s underpowered compared to GWM/Sharpshooter/Tavern Brawler), but even in comparison to my other pure class builds that I’m playing relatively blindly it feels embarrassingly weak, so I’m turning to you guys for help. I’m pretty new to DND/5e in general, and while I think I have an understanding of the basic mechanics, it always feels like I have a lot more to learn.

I’ve already read threads such as Dual Wielding: Multiclassing and you, ]Understanding Dual Wielding]( https://www.reddit.com/r/BG3Builds/comments/16szwlb/guide_to_understanding_dual_wielding_in_bg3/), but up until I get the legendary items in act 3, it feels like my build is very lack luster. On top of that, it seems like the consensus is that Thief >>> Assassin because of the extra bonus action.

The closest thing I’ve come to is something along the lines of Gloomstalker 5 + Assassin 4 + Champion 3, but it feels like it takes so long to come online (At lvl 9, I’ve only just dipped into fighter)

Edit: Any links to previous builds that've been posted in this subreddit will be greatly appreciated as I likely have missed things.