why is sqrt(factorial(l)*factorial(l))-factorial(l) not 0

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I am checking solutions of some field equations. The check requires at some point the calculation of something like sqrt(factorial(l)*factorial(l))-factorial(l) where l is a positive integer . Sage gives |l!| - l! rather than 0. It works for explicit values of l. I have also tried declaring l as a positive integer and using .canonicalize_radical() and .simplify_full() as shown in the code snippet below, which has some of the lines commented out. I'm using Sagemath 10.5 on a MacBook Pro with Sequoia 15.3.1

version()
var('l')
assume(l, 'integer')
assume(l>0)

# l = 273
x = sqrt(factorial(l)*factorial(l))-factorial(l)
#y = x.expand().canonicalize_radical().simplify_full()
#z = x.expand().simplify_full().canonicalize_radical()
pretty_print('x = \t', x)
pretty_print('y = \t' ,y)
pretty_print('z = \t', z)

How might I get round this issue, please?