Life on Earth without a magnetic field?

First of all: lack of metals would affect life much more than solar radiation. To the point when life would not be possible. There were a period on Earth, before the oxygen catastrophe, when all oceans were red-brown or dark-green (there is no single major theory), due to rust. The Ocean was full of dissolved iron and that was the base of "The Life Soup" where early life formed and developed. Without enough concentrations of iron that would not be possible. But Mars has quite a lot of metals and still has no strong magnetic field - so same can be with our Non-Magnetic-Earth.

Second of all: most radiation (75 μSv/h) comes from "cosmic rays", not from the Sun. So there is little sence to reposition a planet. Sun non-EM radiation can be fully shielded with millimeters of aluminium. Thick Earth's atmosphere would be enough to not be afraid of Sun.

For reference: "standart background radiation" is about 10-20 μSv/h. Dangerous levels begin with >40 μSv/h - for humans, who want to leave up to 80 years old more or less healthy

So what would be the consequences?

Radiation would not prevent appearnce and spread of life. Early Earth were more radiated than modern Earth due to higher geological activity. Even now newly-formed or active geological areas can have background radiation levels at open air 10 times more then normal background - up to 100 μSv/h. Which is more than cosmic radiation. I have personaly grew up in such an area (there were a lot of granite and basalt rocks and cliffs around) and can assure you - life is more than comfortable in there (of cause it has consequences for human health on long term - canser rate is double or triple of that for the "main land").

But that a short-term perspective. On long term thing are much worse.

At first our planet had no oxygen. Than some microorganisms appeared that inveted oxygen production as a weapon against others. Yes, at first oxygen was poisonous for life. And then for billions of year oxygen very slowly accumulated on Earth. But that is the problem. Since oxygen is much lighter than then-main component of air - CO2, it were accumulated mostly in high atmosphere. And without any magnetic field solar wind would just blow it away. It does so even now (mostly for hydrogen - but about that later) but at many orders slower rate.

So Non-Magnetic-Earth would most likely be unable to accumulate enough oxygen and there would be no oxygen-based life. For now we (I at least) do not know any complex anaerobic organisms. But that doesn't mean that this is impossible. It is a pure speculation field. You have some freedom of "invention" here.

This process of "blowing away" also consern such a vital substance as water. Water vapor also lighter than CO2. It dissolves to ozone and hydrogen due to radiation in upper atmosphere. And hydrogen is much more prone to be blown away than any other element (since it is the lightest). It means that water would also be slowly lost. But, unlike early oxygen, there were (and is) so much water on Earth, that that would not affect early stages of life much. Mars had water for very long period of time - and it was loosing it at times higher rate due to low gravity. With Earth's gravity it still would had lots of free water.

So Non-Magnetic-Earth would have visibly less water than modern Earth at the same age, but it still would be enough of it to support life.

About UV - that is not that large problem on planet scale. If we would somehow remove all UV protection from atmosphere now - it would not kill life on surface. It will not even kill the humanity. Biosphere would change, of cause, adapt. People and animals would become darker (to protect from UV) or lighter (to reflect it). More animals (and may be even humans) would become nocturnal. But at global geological scale there would be nothing dramatic.