Chromium on iPhone and iPad
Why no real Chromium build exists for iOS, what Chrome for iOS actually is, and what changed with the EU's alternative engine rules.
There is no genuine Chromium build for iPhone or iPad, and the reason is Apple's rules rather than any technical limitation.
What Chrome for iOS actually is
Apple's App Store guidelines have long required that browsers on iOS use WebKit, the engine behind Safari. Chrome for iOS therefore uses WebKit, not Blink. It carries Chrome's interface, sync and account integration, but the part that actually renders pages is Safari's.
That is why every iOS browser scores identically on rendering tests, and why a site that breaks in Safari on iOS breaks in Chrome for iOS too. Underneath, they are the same engine.
Since Chromium is essentially Blink plus a browser around it, a WebKit-based build is not really Chromium in any meaningful sense.
What changed in the EU
The Digital Markets Act forced Apple to allow alternative browser engines on iOS in the European Union, and iOS 17.4 added the technical mechanism for it.
Uptake has been slow. The entitlement carries substantial conditions, an EU-only build is a separate product to develop and support, and the commercial case for maintaining a whole second engine port for one region has been weak. As of this writing there is no shipping Blink-based iOS browser in general availability, and certainly no community Chromium build.
If that changes it will come from Google rather than a volunteer maintainer, because the entitlement process is not something an individual can realistically satisfy.
What you can actually do
Use Chrome for iOS if you want Chrome's sync, account integration and interface. You will get WebKit rendering, which for ordinary browsing is perfectly good.
Use Safari if the interface does not matter to you. It is the same engine with better system integration and better battery behaviour.
Use a content blocker if ad blocking is the goal. iOS content blockers work at the WebKit level and apply across every browser on the device, which is a genuinely better arrangement than per-browser extensions.
If you specifically want Chromium, that means a desktop or Android device. See Chromium for Android, where real Chromium builds do exist and can be sideloaded freely.