Trying to forward Serial1 reading to Serial.println and only getting numbers

I have a battery with a built-in BMS that has a serial console port. It has a baud rate of 115200 and I have been able to successfully send commands and read clean data from it via the Arduino IDE serial console. Considering I can communicate to the battery via the serial console, that suggests there shouldn't be any weird encoding issues.

I want an Arduino Mega to read from this using the Serial1 connection. The problem is, if I try to forward what the battery sends to the Arduino, all I get is a jumble of nothing but numbers. When connecting to the BMS directly, typing "help", the output is mostly text.

Here's what I tried in void loop()

while (Serial.available() > 0 {
  Serial1.print(Serial.read());
}

while (Serial1.available() > 0) {
  //THE NEXT 4 LINES ARE VARIOUS THINGS I TRIED,
  //I UNCOMMENTED THEM ONE AT A TIME
  //String incomingtext=Serial1.readString();
  //char incomingtext=(char)Serial1.read();
  //char incomingtext=Serial1.read();
  //int incomingtext=Serial1.read();
  
  //I ALSO TRIED THE FOLLOWING ONE AT A TIME WITH EACH ABOVE COMBO
  //Serial.println(incomingtext);
  //Serial.println((char)incomingtext);
  //Serial.println(" "+incomingtext);
}

The first while() loop just takes whatever I enter from the serial console through USB to the BMS. I have no idea if the BMS is receiving the correct commands, but it does have a consistent output if I type different things.

Whenever I type "help" repeatedly, it's usually a consistent output, like this:

10410110811213