I need help finding a good weapon for the dark brotherhood

anything once you get high smithing.

dragonbone weapons have the highest base damage, while ebony and daedric do the same amount of damage as each other. what type of weapon anyway? sword? dagger? bow?

Thanks

I might choose dagger, and I might try to get astride dagger

The best weapon is the one your character likes the most.

Thanks

...
I might make a new character that's an argonian. Any races you'd recommend?

Whatever you like the best. The differences between the races are mostly aesthetic. I like Altmer and Khajiit the best.

a plastic spoon

no serious , every weapon once you start having good weaponskill and smithing skill is a good weapon tho each od them require and slightly differnt combat style depending on its speed and reach

other than that it is personal choice