As an award committee, which one is better?

First of all I would set things in a way that panel of judges will be the one making final decision and could "overtake" other results combined (digitals+sales+fan vote). And of course judges should also have that reality check to not vote for groups which didn't really shine that much this year.

This years GG/rookie GG of the year is good example

maybe building a tiers would be even better to put it into perspective.

Girl group of the Year is main title

and rookie gg of the year is one tier below

Let's say we have Idle and IVE like now in 2022

Idle is making comeback on 17th October, and your award show is in late november/early december

You need to be smart about it, let's say Idle hit it big again with comeback then it's obvious thing that GG title should go to Idle, and rookie title should go to IVE, but then in you have problem in rookie section because of NewJeans existence, and because Le Sserafim is making comeback too and they will have big preorders this time around.

So what do you do next? As it is rookie award, and different award shows already did it in the past, you 'open' another bracket, and give two awards to GG's in rookie category: IVE & Le Sserafim

then you 'grant' NewJeans, a "Breakthrough of the Year" award

And for another happy ending you give "Performance of the Year" award to one of groups like TWICE, ITZY or STAYC which were active for whole year, and this is the meaning of "performance" award, it is for performers, not for sitting asses in home.