you say gaara but all I think of is Juugo.Not really. I mean he's probably the most nuanced and developed character introduced in the New Era, besides maybe Boruto himself. He's one of the only characters related to the whole Otsutsuki plot that can actually be empathised with.
But its all stuff we've seen before. He's got the attitude, curse mark and similar choices ahead of him to Sasuke. Plus the daddy issues and uncontrollable horror-esque power from Gaara.