As a guy who plays Payday and has struggled with "how do I make a cosplay not just look like 'generic man in suit'?" I can offer a few tips.
If you don't want to use your hair (or a simple wig - you can go CHEAP since it'll be mostly covered) at least get a smaller or tighter skullcap beanie. Something like a spandex helmet liner won't be as bulky and can add a 'tactical' look that fits the character. Can't help you on beard styling (I get not shaving but even a trim might help) but it could be fun to add some temporary white coloring to match Etebari's salt-and-pepper beard a little closer.
Even if he has a black suit in promo pics his funky brown blazer is more iconic imo. Since you have a couple weeks it'd be worth it to cruise through local thrift shops to see if there's a cheap suit jacket closer to his ingame look - doesn't have to be identical, but if you get lucky and find a brown tweed in roughly your size I think it'd look nicer.
Also keep your jacket unbuttoned since that's how the character models look.
I can't tell if you're wearing something strapped on in the pics, but some more accessories would go a long way. Since you'll probably want a bag anyway for stuff you get at the con, try something resembling the duffle or shoulder bags from the game. Even something as goofy as fake money poking out of your pockets is something people would find fun.
Some cheap craft-store paint touchups would make your mask look nicer - darker blue for the star back, and maybe a bit of weathering around the eyes and brow to make the sculpt 'pop' some more.
not really, you gotta lean into it