It's hard to survive on very low wages. That's one reason we have a social safety net. Many argue that it should be the company's responsibility to pay their workers higher wages and not society's responsibility to take care of unskilled members of society. However, this is not a realistic option in all cases because some fraction of these jobs would cease to exist if higher wages are mandated as not all customers will be willing to pay higher prices. In the food delivery case it's a large fraction of customers and the business will probably cease to exist.
The fundamental problem here is that our economy is becoming more advanced and more and different skills are being required to be able to provide value to society and many people don't have the required skills. There are only a few things that can happen in this scenario: society educates low skill residents to prepare them for more valuable jobs, low skill residents work in low value jobs, low skill residents are unemployed. We should make the education option available and highly encouraged. We should provide for necessities like nutrition, safety, shelter that many young people are lacking that prevent them from availing themselves of educational opportunities. However, in the case that people aren't willing or able to complete the education required for jobs requiring a highly educated workforce, I think it's better that people have the option of working in lower value jobs rather than effectively outlawing it. This does not mean these workers should be treated as having low value beyond being paid low wages. There should be worker protections, customers should treat workers with respect, etc.
It would be better for the world if we had more people working in more valuable jobs like science, medicine, technology, etc. and fewer in food delivery. But raising wage regulations to the point that Deliveroo's business model is no longer sustainable probably just means that its workers are unemployed and people have fewer food delivery options.