I also considered Kagi a bit and I think it might work if I start to change my search behavior. I got too used to abusing search engines as a quicker way to open websites (I could use bookmarks for that) or for bangs (I could use the browser itself for that).
If I managed to untrain myself from this and start using tools for their core-purpose, the limits of Kagi might indeed be more than enough. But currently I am too lazy for such a deep change in my daily workflows.