There are few things in D&D 5E on which the consensus is as overwhelming as on the fact that True Strike is an extremely poor cantrip. As discussed in many places, the main problem is the action economy. As this answer to a similar question puts it, casting True Strike is not so much a benefit as it is a trade off: You waste your action on one turn in order to gain advantage and thus use your action more effectively on your next turn. As has also been pointed out countless times, this is rarely optimal, as attacking twice without advantage still has a better chance of hitting at least once than attacking once with advantage.
The generic scenario in which True Strike actually helps is when a character needs to put all their focus into making sure that one crucial, strategically relevant attack actually hits. Putting it like that doesn’t let it sound particularly magical: the character just takes their time to aim.
Would it be balanced to introduce an Aim Action, that is available to everyone and does exactly what True Strike does (mechanically)?
I also noticed that the Unearthed Arcana Class Feature Variants include the "Cunning Action: Aim" for the rogue. Having a general Aim Action and allowing this feature variant would keep in line with the idea that the Cunning Action lets the rogue do things anyone can do, just quicker. It’s Unearthed Arcana, so this may not be a great argument, but I like how consistent it feels.