That's not consistent between phones. I have a low end Redmi 9T with a 6AH battery. It lasts 2 days of relatively heavy phone usage. I'm guessing it would last a whole day in a Termux shell.

Edit: if anything the real issue is thermals. I also have a high end phone with a Snapdragon 888. This thing has a faster CPU & GPU than my Intel desktop. However, it's only fast for seconds, until it gets thermally throttled.