Hi Kiyoshi,
The panic log you've posted is showing that an I2C bus clock line is stuck low somewhere. I2C0 goes to the wide angle camera, the battery connector and the charge port assembly, and a couple other places. So yes, this is a hardware failure.
We saw the same error on an iPhone XR a year or so ago, and in that case it turned out to be the charging port flex assembly. That's where I'd start, with replacing that.
[post|713457|SOLVED: iPhone Xr randomly bootloop at random moment - iPhone XR - iFixit|new_window=true]