Right now, I'm sending Json from 4 EPS32s to a central ESP32 using the HTTPServer via POST. I'm concerned about data not getting through.
I did point-to-point TCP at one time, but that was more headache that it was worth.
I don't want to use any service that requires the internet as my internet is not so reliable at times. (Comcast. Go figure.)
I don't have a Raspberry and funds aren't plentiful at this point.
I've looked at ESP-NOW and the write ups I've encountered appeared to make it as through 4 units talking to the central wouldn't work. (The central feeds a Due with a touch screen.)