you can use ublock lite if its ios 16 or newer. or adguard for older versions.

alternatively theres reynard browser which is a full gecko firefox port and also runs ublock origin

Yup. install the Orion Browser. It has adblocking built in. Then install the Piefed Web application from Orion.

Or, if you wanted phone wide, configure adguard dns: https://adguard-dns.io/en/public-dns.html

Here you go!