After the enterprise grace period the code will be deleted from the project. You can expect a fork to appear that patches it back in (I doubt ungoogled chromium would be where that is done), but eventually that will become a nontrivial process. You have a year, maybe two. There are many chromium-based browsers that have built-in blocking.
(Old habits die hard)
There's https://github.com/ungoogled-software/ungoogled-chromium - is it a sound choice nowadays?