Try Orion browser on iOS/iPad. Afaik it’s the only browser that implements web extensions, therefore you can install any native firefox or chrome extension from the store.
Just stumbled upon that yesterday and gave it a try. While I could "install" uBlock Origin, it didn't seem to have any effect and the configuration page for it was completely blank. They also say "Orion even supports some extensions out of the box on iOS, but we have much more to do here" on their page, so I guess it's not there yet.
