There are lots of cards that give you mana in increments of three, and most lifelink creatures worth playing already have three power or more
Experiment Kraj A classic Simic commander thats been eclipsed by the power creep of ETB triggers over activated abilities, Experiment Kraj is definitely aboil in Agatha's Soul Cauldron
That said, its also often fine to just use Brainstorm as a cantrip if you have to I feel like some people swing too far in the other direction and refuse to cast it unless theyre getting a lot of value, but the beauty of the card is that it can be cast in many different ways, so you should not impose this restriction on yourself
However, you can blink Loot or find some other way to reset him so you can keep activating whichever ability you need most
That being said, the Turtle Warrior is still a strong artifact payoff
It can't be blocked this turn.At the beginning of each opponent's end step, if that player has less than half their starting life total, abandon this scheme