I agree with you about the issue of digital ID. It will do nothing whatsoever to deter "illegal migration".
The underlying issue with the "black economy" of illegal workers is not the same as the one of asylum seekers though.
Since there are no "safe and legal" routes for people to legitimately claim asylum in the UK if they come from many places, people desperate to come here and do so (for whatever reason) are forced to come in small boats, or hidden inside lorries. It's extremely dangerous, and nobody in their right mind would do it if they had any option. Once in the asylum system, such people are left in limbo while their claims are processed (with the huge, politically created, backlog). Whilst this happens, they have to be housed and fed. They get given nothing more than this, and are not entitled to work to support themselves. These are human beings, and all humans have basic needs, which in this case are barely being met. The language being used to describe them as "illegals", and words like "swarm" and "invasion" are exactly the same as those used in 1930s Germany to scapegoat people; dehumanisation allows people to do terrible things.
The black economy, on the other hand, of undocumented people working illegally, is a completely different issue. These aren't people in the asylum system, they are people who have been smuggled into the country, often in conditions of modern slavery. They enjoy no rights, no social security, no access to healthcare or education, nada, as far as the state is concerned, they do not exist. These people are absolutely victims. I actually know someone who was lucky enough to escape from this situation; he was lured from his home country with the promise of work, and when he arrived here had his identity documents and passport taken, was forced to work unpaid, and when he escaped, his family at home were threatened. He was then recaptured by his slavers, tortured (he has scars all over his back from cigarette burns), before eventually escaping again, and finally managing to claim asylum, through a very long and difficult process. He is now a successful business owner who contributes towards the UK economy. This all happened in the early 2000s, if it had happened today, he would probably be dead instead.
The point is that such people aren't "sat safely on a beach" in France. They are often under the control of criminal gangs from the moment they leave their home country. Many have escaped from war zones or from countries where they are being persecuted as a minority, or due to their sexuality or religious beliefs. They will have endured a dangerous journey in conditions under which it would be illegal to transport cattle. Many won't even know which country they are headed towards, or their final fate. Those who are deliberately trying to come to the UK are almost all doing so to reunite with family members. If your spouse had escaped from a war zone to a safe country, it seems only fair that you might want to try to join them. The safe legal routes to do so, which used to exist, have been removed by previous governments. As it is, most refugees don't come to the UK; pretty much every country in Europe takes vastly more immigrants than we do.
In any case, you misunderstand my point, the digital ID stuff is clear and obvious bollocks, as I have said in another thread, those employing modern slaves in the black economy already don't do the existing mandatory employment checks, and they won't check ID cards either. If anything a new mandatory ID will give modern slavers another thing which they can seize from a victim and use to control them. Not all modern slaves are immigrants, many vulnerable people who are UK citizens get exploited by the same types of criminal. Look up "cuckooing" and county lines gangs for some good examples.
I simply take a strong objection to the increasing characterisation of other human beings as untermenschen. I don't like fascism, and when I spot it, I tend to call it out. Any right thinking person should do the same. "Illegal immigrants" are an easy target, because they are pretty much the most vulnerable people on the planet, with very few rights or ability to defend themselves. They make a very convenient target for the rich powerful people who want you to be distracted from their own activities of pillaging the public purse.
I do agree with you on one point here, the UK shouldn't "bankrupt itself". Follow the money; it isn't going to immigrants, it's going to billionaires. Use your brain, join the dots, don't listen to the well-funded far-right propaganda.