Okay, three things, least important first:

Using “net” positive already refers to comparing it against the negative. If you want just the positive before comparison, use “gross”.

Second, there is no positive to eugenics. There are hypothetical gains to make but they are unrealizable. This is because the mechanisms to decide who gets to reproduce will immediately be corrupted. Immediately. Every time.

And finally, the negatives are huge. Personal anguish, public unrest, widespread violation of civil rights depending on how draconian you make your regime, the downsides are huge and certain.

So unrealizable and uncertain gains at the a huge and certain price: No. No eugenics.

If you want to personally have lots of children with smart, beautiful, talented people, well, get in line.