The launch of Mega Evolution will not only mark the end of the TCG's current Scarlet and Violet block, but it will also start an all-new era of the game, themed around the gameplay mechanic that it's named after
Depending on the board state, this card alone can decimate the game, taking a significant chunk of your opponents life out in a single turn
I think you're right though that the first version might be better suited, especially in proactive Decks
What I mean by that is, you can use it to exile an opposing creature for as long as the Bodyguard sticks around, or you can use it on one of your own creatures
If you were already playing an artifact heavy reanimator deck in these colors, Jan Jansen, Chaos Crafter is also right at home in those builds too, but Ill be honest, I have yet to see a deck like the one this card enables
Karn has truly been Liberated in his latest reprint