As for the bow itself, it would need to be relatively easy to draw, yet still have good release velocity.
This requirement categorically rules out bows (as well as weapons operating under similar principles, like slingshots), because the energy contained in an arrow is entirely supplied by the user's strength. Powerful bows require strong wielders and practice to effectively exert that strength.
There's a technology contemporary to bows that alleviated this.
Specifically, Arbalests get around the issue of being limited to the user's ability to exert force by distributing that force with a winch. Using modern or science-fictional materials, you can have an arbalest with a very favorable gear ratio that can store a tremendous amount of energy while being easy to wind. The downside is that the easier it is to wind, the longer it will take to do so.
However, regardless of how this arrow or bolt is launched, your fundamental problem is that a slow-moving, heavy projectile is not effective as a weapon. Kinetic energy is linearly proportional to mass, but quadratically proportional to velocity. Higher velocities also increase range and accuracy, requiring less compensation for gravity.
For reference, where hunting bows tend to have around 50ftlbs of energy, common 9mm handgun ammunition has around 300ftlbs, giving it much greater range and armor-piercing ability. In order for this slow projectile to be a practical weapon in a sci-fi context, it needs to derive its killing power from something other than its kinetic energy. Thankfully, we already have the perfect solution.
Or a derivative. A 40mm grenade launched from a handheld launcher travels at about 75m/s, comparable to crossbows, while being easy to load and fire and having softer recoil than its caliber would suggest. A variety of projectile types are available, ranging from dumb slugs (training rounds) to high-explosive to HEAT to buckshot to flechettes.
If a single-shot weapon isn't effective enough, try pump-action or revolving. You can deliver a much higher practical rate of fire than a bow, with much greater lethal potential.