Help me Spend my gems

Hi,

Returned to game after a long long break.

I currently have almost 20k gems to spend. I have many “staple” cards from before I stopped playing and the last deck I played in pvp would have been Speedroids with Crystal Wing Dragon.

I’m not looking to play Hero or Salamangreat decks.

Thoughts I do have are to finally get the Invoked cards/engine or to go after Rokket/Borrel cards.

Are either of these a worthwhile investment? Invoked certainly have seen play for years.

Any other recommendations?