As soon as you resolve Heliods lifelink ability targeting your Ballista (or it gains lifelink from some other source) you can shoot for an easy win, since removing a counter from the Ballista to deal damage will also lifelink for one, triggering Heliod to reload the Ballista for you
However, King of the Oathbreakerss a good card as a payoff in phasing decks, though itd have been much better at 3 mana rather than 4
Inversely, if youre playing a deck thats likely to frequently wipe the board clean, avoid mana dorks
That said, at nearly $20 each, I wouldn't blame you for going with the New Capenna version
Shadowheart's Devotion Shadowheart, Dark Justiciar - $0.50 Nonfoil / $1.20 Foil Beseech the Queen - $4.10 Nonfoil / $6.60 Foil Black Market - $4.10 Nonfoil / $5.60 Foil Victimize - $0.50 Nonfoil / $0.95 Foil Ancient Bronze Dragon - $18 Nonfoil / $20 Foil Total = $27.20 Nonfoil / $34.35 Foil Shadowheart's drop is a bit better than Gale's, with higher card quality overall and one card, Ancient Bronze Dragon, almost pushing it up to the $30 mark