Right, so JavaSnipt kinda just works for me. I have it set to block by default, and I unblock sites by opening the share sheet in Safari and tapping on “JavaSnipt”.
As for CSE, you can literally set the search engine to anything. I currently don’t use it, as I have gone back to Ecosia for now, but I previously used it with SearXNG, 4get, and even Ahmia.