I do not enjoy raining on your parade, but - we need some realism.
15-minute neighbourhood is a totally unworkable concept.
People can do grocery shopping and send children to a local school. That largely happens already. With a considerable effort, local availability of primary health care / family doctors can be assured (perhaps). Need to fix the shortage of doctors for that, but at least this is doable in theory.
Everything else requires longer trips in a big city. Most of people will not find a job that needs their particular skill set in the 15-minute neighbourhood. You can't build a hospital or a university in every 15-minute neighbourhood. To reach a surgeon or a kidney expert, to enroll in a post-secondary program that fits your passion, you will need to travel longer. Probably, you will need to cross half of the city. Even for retail shopping, people will find a better choice and/or a better price away from their home, unless you abolish all competition between the retailers and make them all carry the same set of goods for the same price.
The only viable 15-minute neighbourhood, is an isolated 19-th century village. Where everyone works in the field, at the local blacksmith's, or in the local shop (one for the whole village). All kids go to the local school (grade 1-4), noone needs more education. Modern high-tech jobs or advanced medical procedures are unheard of.