Upgrade Help

I was wondering what I should use my 5.4 million gold on. I have two builders available.

Currently I have....
1 Lvl 8 AT
5 Lvl 10 AT
1 Lvl 4 WT
1 Lvl 6 WT
2 Lvl 7 WT
5 Lvl 10 Cannons
3 Lvl 7 Mortars
1 Lvl 4 AD
3 Lvl 5 AD
7 Lvl 5 Walls
65 Lvl 6 Walls
178 Lvl 7 Walls
4 Lvl 4 Teslas
2 Lvl 1 Xbows

The three options I thought of are upgrading another WT to Lvl 7, or a xbow to Lvl 2, or 27 walls to Lvl 7.

What should I upgrade?
(sorry if this is in the wrong sub forum)

xbow. Good for the long term.
Wt lvl 7 would be my second choice.

That's what I was thinking but I feel like my walls are pretty far behind for a TH9.

Your wizard tower is still too low, upgrade them first, spend whatever extra on walls. Anything less than lv7 walls at hall 9 is a no-no.

I've been trying to catchup on my walls. I just don't like having builders sleep.