how can i sort a list with recursion without using the sort function?

You don’t need to keep track of two lists. The following works fine:

def gensort(L):
    if len(L) == 1:
        return L
    sorted_list = [min(L)]
    L.remove(min(L))
    return sorted_list + gensort(L)

Here’s what’s happening:

gensort([4, 1, 3, 2]) # returns [1] + gensort([4, 3, 2])
gensort([4, 3, 2]) # returns [2] + gensort([4, 3])
gensort([4, 3]) # returns [3] + gensort([4])
gensort([4]) # returns [4]

Substituting in the return values, you get:

[1] + [2] + [3] + [4]

Which evaluates to [1, 2, 3, 4].