Vitamin D supplements are controversial on their own.
There is ample results on better health correlated with higher levels of Vitamin D, but the reverse is far more teneous: shoving in Vitamin D isn't guaranteed to be properly absorbed, and even when it is we don't see conparable results to people producing the Vitamin D themselves.
An example: https://academic.oup.com/jbmr/article/38/10/1391/7610360
The paper you linked is saying there is no benefit in Vitamin D supplementation in people who are not Vitamin D deficient. Which is not surprising.
Do you have research showing sunlight Vitamin D has benefit for someone who is not deficient?
Unless you are deficient it's not the vitamin D. It's a whole host of other processes that benefit your body from sun exposure and the activities that go along with it. The Vitamin D is just a marker that we can detect that can also be related to that same exposure. So there's a huge number of things for which people with high levels of Vitamin D do not suffer but supplementing has no effect because the vitamin D is only correlated not causative.
The paper covers a lot, some are administrating vitamin D as a prevention measure, most are on vitamin D deficient patients. e.g
> Even in the small subgroup of subjects with a poorer vitamin D status (serum 25OHD < 20 ng/mL), no effect on fracture risk was observed (hazard ratio [HR] = 1.07; 95% confidence interval [CI] 0.91–1.25).
> A large RCT in Mongolian children with severe vitamin D deficiency did not find a beneficial effect of vitamin D supplementation on the subsequent risk of subclinical or clinical tuberculosis.