I love kagi but I hate this. It's not their fault, it's just a limitation of the os but it's such a hassle when you have to solve a Google captcha to get kagi results. I'm considering just removing that from my phone and switching back to Google there.
You can switch default search engine to DDG or Ecosia, Kagi extension will still redirect you away. Or use extensions like xSearch or xEngine, they seem to be better at redirecting
That's exactly what I do. I feed searches to Ecosia and the Kagi extension handles the rewrite. Works well on Mac and iOS. I only use Google explicitly with the !g operator (which I use sparingly, and often get the same results or slightly worse) or for Google Images (which are better for now)