The most desirable areas to live are not for the average salaries.
Don’t get me wrong, I think housing is one of the most basic rights that every human being should have. That doesn’t mean rent should be as cheap in highly desirable areas as in not so desirable ones. If people are living around big populous cities due to work then make public transport good, cheap etc.
35% is a touch high but not out of line with the 30%ish recommendations from banks/estate agents over the years.
It might be an issue that the cost of the average 1br flat isn't attainable on a single average income. But I think we can see how we arrived here.
You need to redo your math. The effort rate is calculated taking into account all fixed monthly expenses, not just rent.
By your own numbers, rent alone is already higher than the maximum admissible effort rate for a household with above average incomes. On top of this you still need to account for your actual cost of living.
You're looking at a scenario where a household with an average or above average income has to endure a effort rate well above 40%-50% to afford living in Barcelona.
To make matters worse, in Barcelona rents do not drop that much even if you start to entertain commutes of well over 2h/day.
There's nothing healthy about it.
You have to pay €950 for an apartment 30km away because the average rent in the city center is €2000.
The average salary in Barcelona is €2800, whereas the average rent is €2000.
Do you understand the problem? I mean, answer your own question. Why do you pay €950/month to live in the boonies? Would you pay €950/month to live 30km away if you could pay less than that to live closer to the city center?