networkx digraph matplotlib graph orientation

I am trying to create a graph using Networkx Dograph and matplotlib, this is my code

def draw(self):
    # Create a directed graph object
    G = nx.DiGraph()
    # Set node colors
    node_colors = []
    for tx in self.transactions.values():
        #print("batch numer", self.num_batches)
        if tx.txid == '1':
            node_colors.append('orange')  # orange for tips
        elif tx.txid == '0' and self.current_batch == 0:
            node_colors.append('grey')  # gray for first transaction
        elif tx in self.tips:
            node_colors.append('grey')  # gray for tips
        else:
            node_colors.append('blue')  # blue for other nodes

    # Get node positions and heights
    pos = {}
    heights = {}
    for tx in self.transactions.values():
        if tx.txid == '0':
            pos[tx.txid] = (0, 0)
            heights[tx.txid] = 0
        else:
            max_height = max(heights[parent_txid] for parent_txid in tx.parent_txids)
            pos[tx.txid] = (max_height + 1, len(heights))
            heights[tx.txid] = max_height + 1

    # Add edges to the graph
    for tx in self.transactions.values():
        for parent_txid in tx.parent_txids:
            G.add_edge(tx.txid, parent_txid)

    # Draw the graph
    plt.figure(figsize=(10, 5))
    nx.draw(G, pos=pos, with_labels=True, node_color=node_colors, node_size=1000, node_shape='s')
    #plt.axis('equal')
    plt.ylim(-1, len(heights))
    plt.xlim(-1, max(heights.values()) + 1)
    plt.show()

this is the output

The inked version is how I want it, node 0 should be in the mid at left most side and later nodes shod grow horizontly but not vertically. curenttly, the new node grow horizontally but also vertically. I have tried to play with
plt.ylim(-1, len(heights)) plt.xlim(-1, max(heights.values()) + 1) but cannot fix it, it will be great if someone can help me fix it. and please let me know if the question is not clear.

I think what you're looking for is much easier than you are making it:

Check out this post for reference.

If you add a simple

from networkx.drawing.nx_agraph import graphviz_layout

and change your

> nx.draw(G, pos=pos, with_labels=True, node_color=node_colors, node_size=1000, node_shape='s')

to

nx.draw(G, graphviz_layout(G, prog='dot', args="-Grankdir=RL"), with_labels=True, node_color=node_colors, node_size=1000, node_shape='s')

you should be good to go.
I recreated your use case and it resulted in this graph (don't mind the coloring, I did not take the time to adjust that to your use case):

Drawing graphs is not a trivial task and you should try and look for existing algorithms to do the layout for you whenever possible.
For future questions:

Try to provide a minimal working example of your problem. From your question alone it is not easily possible to recreate your issue because you did not provide the exact nature of "transactions", "tips" or "current_batch" (the 2 last ones would actually be better to leave out since they are not part of the problem).

Hope this helps