BG: Gold upgrades on T5 are always awful for me

I don’t get how ppl do it, but at least 8/10 sets I make when I’m at T5, give me nothing to match my board with…

Two perfect examples:
Last game I had a quillboar board with a big Cave Hydra. I made 4 sets when I was in T5/T6, from all 4 all the T6 discoveries I had Kalecgos 3x, Nadina 2x , Zapp 3x, D.A. Aliza 1, Tide Razor 2x and Maexxna 1x.

3 games ago I played a full Elemental board and picked up 4 sets at T5 as well. That time it gave me: Gentle Djinni 1x and the rest were Kangors Apprentice, Tide Razor, D.A. Aliza, Foe Reaper, Goldrinn and Zapp, only can’t remember how many of each there were.

I know the chance is bigger that you’re not getting what you need, but this is my average and I really don’t know why my odds are that bad