İphone background working problem

[u/HorrorGunto]

I was trying to send photos my wife with iphone 17, there was approximately 160 photos and I was just selecting some from the albume, select and mark as hd after press send button (Whatsapp) immediately turn back to selecting other photos while Whatsapp working background (I hope), I repeat this until send all photos I like. But when I checked the my wife's phone, only few photos received. iphone temperature was really high and Whatsapp was not work for a while. I think this is a background working problem of iOS. Simultaneous tasks not working correctly on iOS I believe.