Mathematica precision differs from other calculators

Mathematica's model of approximate decimal numbers is different from almost everyone else's model of approximate decimal numbers.

Because of the number of digits you supplied for each of 123.432654 and 54.1122356 these are assumed to be and treated as MachinePrecision numbers. That means they have the usual "about 16 digits of precision as supplied by the CPU floating point hardware in your computer, but it is a little more complicated than that.

Because of precedence rules Mathematica first evaluated each of those numbers and converted them to the internal floating point form, with the limited accuracy and all the problems that brings and all the speed of being able to perform calculations in hardware instead of software.

Then it did the division using the internal floating point hardware which resulted in another MachinePrecision number with only about 16 digits of precision.

Then with DecimalForm you asked Mathematica to extrapolate that result with only about 16 good digits into a 130 digit display.

All, or almost all with some very subtle things in dark corners, of the *Form functions are intended to and only used to produce something that can be displayed and not used for further calculations. For example, new users routinely do m=MatrixForm[mymatrix] to see a pretty formatting of the matrix and then proceed to try to do calculations with m, which fails.

Then you asked Mathematica to perform the SetPrecision function on that display to try to turn that into a 130 bit precision number. I can't even guess what that really did internally.

It seems those other calculators assume that the precision of the entered numbers is infinite. WL does not. You can specify what precision the entered numbers have e.g.

123.432654`30/54.1122356`30

2.28104887242914059163358610155