Would you help me with the corrections to the code?
It would be more instructive and you would learn more if you made the changes yourself with help as to what you need to do, but you do not seem to listen.
lcd.clear(); //do not clear the entire LCD. Position the cursor and print 5 spaces over the number
char displayText[18] = ""; //totally unnecessary
snprintf(displayText, sizeof(displayText), "Set Count:%5d", key - '0'); //and this
lcd.setCursor(0, 0); //position the cursor where you want to print the full number
lcd.print(displayText); //print the digits string not the 18 character mostly empty string