Although the CMS usually has jurisdiction to decide child maintenance rather than the court, the reverse applies where there is exactly equal shared care (true 50:50). This was confirmed in a landmark case last year. Some useful commentary on that case can be found here: https://becket-chambers.co.uk/articles/os-v-dt-shared-care-and-child-maintenance/
It is not the case that a court will never award child maintenance in 50:50 care, but it is of course much less likely. You’ll see in the above case that the court can make other financial orders, for example, requiring one parent to contribute more towards education. They did so despite both parents having ample financial resources, simply because one earned more. The same principle can apply to recreational hobbies, school uniforms, transport, and similar child‑related costs.
Spousal maintenance however, is entirely separate. It depends on need and earning capacity so is very fact‑specific. If your solicitor believes you may be entitled to it, that can be helpful in negotiations. Sometimes it shifts the other side away from trying to avoid child maintenance and insisting on 50:50. Many would prefer to contribute towards the children rather than pay spousal maintenance. And if they pay child maintenance or other child‑related costs, that may reduce the likelihood that spousal maintenance is ordered, particularly in cases where there is not a dramatic difference in income.