There is a systemwide ad-blocker available called MYbloXX[0] that I've been using on a jb iPhone, but you can also use it on a stock iOS device with the caveat that you have to do a device restore to be able to apply the configuration. The web site is a bit cheese but the developer has been doing this for years and it works really well, across all apps. You can see the PAC file it uses here[1]

Alternatively, I've just signed up for the Orion browser beta[2] for Mac and there is a testflight available for iOS. This can apparently use (some) WebExtensions, notably uBlock origin. I cannot run testflight apps on my old jb iPhone so I can't speak to how well it works

[0] https://myxxdev.github.io/depictions/MYbloXXforiOS/MYbloXXfo...

[1] https://myxxfm.com/script

[2] https://browser.kagi.com/