Now I think I’m going to create a magic item that lets you cast True Strike as a bonus action. 1d4+1 charges/day.
Make sure the item allows the true strike 1) allows for the advantage in the same turn AND 2) doesn't require concentration.
Frankly, IMO, you're better off having the item mimic the Tasha's rogue ability "steady aim" (perhaps without the 0 movement requirement) instead? not only better, but a much less murky ability, rules wise.