Can I force iPhone 13 Pro Max to use data over cellular while connected to a non-internet connected Wi-Fi signal?

I have a tennis ball machine that creates a Wi-Fi signal to be used as a remote with my iPhone. It works great. The problem is that the Wi-Fi is local and has not connection to data over the internet. This presents a problem with listening to music or any data driven app. Since I am not actually connected to the internet with my (strong) Wi-Fi signal, I cannot stream music. On one or two occasions my iPhone figured this out and ask to use cellular data. I agreed and both functions worked perfectly together. The problem is that the other 20 or so times the phone did not ask and I cannot fine a way to force this dual use of cellular data with a strong data less Wi-Fi signal. Any suggestions?