I think there are a number of factors.
Population density in the West Midlands authorities is high, particularly Birmingham, Walsall, Sandwell, Dudley, Coventry.
There are many areas with high deprivation, and even those that aren't "deprived" have lower levels of income than many other areas of England. As a consequence of these general living conditions, along with highly polluted air in most urban West Midlands areas, the general health of people in this area is poor, certainly below national averages- there are high levels of obesity, of acquired diabetes, of heart disease, lung/respiratory conditions inc. asthma, all of which are indicated as underlying conditions that exacerbate Covid-19.
That's without looking at any behavioural factors.
One thing of note- in the early stages of the pandemic in Britain, Birmingham was right near the bottom for numbers of cases, when Devon, Hampshire, London we're at the top. Well- there aren't many families in Birmingham that ski, that's for sure!
Now, later along the curve, when we're seeing the effects of the virus passed within the population, now Birmingham is up at the top.
But remember- Birmingham authority is a mega-authority. It has a higher population than other authorities (Greater Manchester as was is divided between ten authorities, London also divided into small authorities)
You would expect Birmingham to have more cases than other authorities.
I fear the death rates will be higher here than other areas due to the variables I have detailed above.