I cannot install new software of 12.4.4 on my iPhone 5s.

I don’t know if this is related, but I note that your phone is in low power mode. It can’t be updated in low power mode.

See this for help with over the air iOS updates, Get help with over-the-air iOS updates - Apple Support

If that does not work, then connect the iPhone to a computer, running the latest version of iTunes and update that way.