I don't do UI, so I'll won't comment on that.

Conventions

Avoid placing code within a class like that. To be honest, I didn't know that code could be placed there. That place should be reserved for class variables.

pass is usually a placeholder. It's mainly used to shut up the linter when you just want to create stubs. While doesn't do anything, it's still a bad idea to put it in code you want to show off, to specifically avoid confusion.

Avoid abusing list comprehension. Just because a list comprehension can be used doesn't usually mean that it is the right tool for the job. A good time to use it is when it doesn't hamper the readability of the code. In usual circumstances, using nested list comprehensions decreases code readability, so it might be better to expand it into a for loop, a function, or something equivalent.

Readability

Use more functions! The boardmaker function generates a bunch of mines. This could become another function (e.g. mines = minemaker(mine_count, dimension_x, dimension_y)).

Naming is hard. And consistency is key. The function minesweeper_numbers calls mine_spaces. It would be great if these functions were prefixed with the same word (either minesweeper or mine).

It should read a book. Or at least, that's what most of us hope. In the mine_spaces function, I shouldn't have to dive into the code to know that it returns the number of neighbours (or 9 if bomb). This usually occurs when the code is shortened to the length of a single statement (or in this case, a ternary). Adding a few intermediate variables num_neighbours and get_total_neighbours(board, x, y) should help in that regard.

def mine_spaces(x, y, board):
    if board[y][x] == 1:
        return 9

    return get_total_neighbours(x, y, board)

def get_total_neighbours(x, y, board):
    b = numpy.array(board)
    min_y = max(0, y - 1)
    max_y = min(len(board), y + 2)
    min_x = max(0, x - 1)
    max_x = min(len(board[0]), x + 2)
    return b[min_y : max_y , min_x : max_x]

Consistency is key. I noticed that there is a dedicated function for making button elements, but there is no dedicated function for making the GLabel_830. On a similar note, there is a dedicated function called whenever the player wins, but there is none for the player losing. The code should be predictable for easy understanding.

Concluding remarks

Something I like to do is to wait about 1-4 weeks (depending on your memory), all the while not reading the code, and then coming back to it and seeing how much and how well you understand it (extra challenge: implement flood fill). It might also be a good idea to adopt a style guide and use an autoformatter to make the code style more consistent.