After a bit of browsing, I identified that ESPNOW and WiFi are interfering with eachother. See this link: ESP8266 - ESP-Now Delivery Failure, but only sometimes - #4 by chrismast
After removing the lines of code where I attempt to connect to my hotspot, including WiFi.begin(WIFI_SSID, WIFI_PASSWORD); , the receiver shows the correct data. The problem might in fact reside in the channel used by ESPNOW being different than WiFi channel, hence the sender fails to push the data to the receiver. I will attempt adapting the code in the link I posted to my project and see if the 2 technologies can run under the same channel without disrupting the data flow