First of all, let me say that I am new to this region of stackexchange and I am not yet completely familiar with the standards here. In particular, I hope this question is not viewed as too vague or too opinion-based. If it is, I apologize.
The general setting
- I want to play a rogue.
- My party needs me in melee.
- I want to choose the Arcane Trickster archetype.
- XGtE or SCAG are allowed.
I am aware that these basic assumptions conflict with the common consensus about strict optimization of a rogue, so we are talking about optimization under constraints, of course.
The main objective is to build this character in a such a way that its most important mechanic, the sneak attack, can be exploited as efficiently as possible: Maximize the opportunities to sneak and the likelihood to actually hit.
The main advantage a melee rogue has over a ranged rogue is that the former is more likely to trigger off-turn sneak attacks via opportunity attacks. This is why my character will be a Human (variant) and take Sentinel as his starting feat. I will also use dual-wielding so that in case of a miss, I can sacrifice my bonus action for a second chance to hit.
The general question
In view of my main objective, are there obvious ways to go from there in terms of multiclassing that are demonstrably optimal or at least superior to a singleclass character?
Doing three to five levels of Fighter Battlemaster or two to six of Wizard Bladesinger (my DM is okay with relaxing the elf requirement) seem like a good place to look for me. But maybe someone has already done the math and can give a more or less definite answer?
Thanks for reading this far and thanks even more for any helpful comment or answer.