How to improve this code to make it time efficient? For-loops, prime numbers

The task was taken from www.codewars.com

The prime numbers are not regularly spaced. For example from 2 to 3 the step is 1. From 3 to 5 the step is 2. From 7 to 11 it is 4. Between 2 and 50 we have the following pairs of 2-steps primes:

3, 5 - 5, 7, - 11, 13, - 17, 19, - 29, 31, - 41, 43

We will write a function step with parameters:

g (integer >= 2) which indicates the step we are looking for,

m (integer >= 2) which gives the start of the search (m inclusive),

n (integer >= m) which gives the end of the search (n inclusive)

In the example above step(2, 2, 50) will return [3, 5] which is the first pair between 2 and 50 with a 2-steps.

So this function should return the first pair of the two prime numbers spaced with a step of g between the limits m, n if these g-steps prime numbers exist otherwise nil or null or None or Nothing or [] or "0, 0" or {0, 0} or 0 0(depending on the language).

Examples: step(2, 5, 7) --> [5, 7] or (5, 7) or {5, 7} or "5 7"

step(2, 5, 5) --> nil or ... or [] in Ocaml or {0, 0} in C++

step(4, 130, 200) --> [163, 167] or (163, 167) or {163, 167}

See more examples for your language in "TESTS"

Remarks: ([193, 197] is also such a 4-steps primes between 130 and 200 but it's not the first pair).

step(6, 100, 110) --> [101, 107] though there is a prime between 101 and 107 which is 103; the pair 101-103 is a 2-step.

Here is my solution, which works perfectly and takes more than it requires to test out, however, I'm trying to optimize this code in order to make it more time-efficient.

def step(g,m,n):

    count = 0
    list= []
    list2 = []
    for num in range(m,n+1):
        if all(num%i!=0 for i in range(2,num)):
            count += 1
            list.append(num)
    

        
    for k in list:
        for q in list:
            if (q-k) > 0:
                if (q-k) == g:
                    list2.append(k)
                    list2.append(q)
            

                
    if not list2:
         return 
    else:
         return  [list2[0],list2[1]]

If you have any suggestions or even sample code, I would appreciate this.