Mac /n Cheese

In addition to several home projects that I am working on, I have to get inventive with menus.
I have used zucchini in the past to make lasagna but now I will try it for mac 'n cheese. I researched on the internet and found a recipe for cheese sauce and another that used zucchinis but since I don't have all the ingredients of any, I try to make my own.

Here are my ingredients:
2 zucchinis
Salt
¼ cup butter
¼ cup flour
2 cups milk
Pepper
Garlic
garlic powder
Cheese about 12 slices

Parmesan cheese

First, I spiralize 2 zucchinis.
Next, I salt them while I make the cheese sauce (salt to remove excess water from the zucchinis).

In a saucepan, I melt the butter.  Then I add the flour, pepper and some salt and mix until smooth.

Next I add the milk slowly while mixing. Then I add my cheese and stir until melted.
Next I rinse the spiralized zucchini and place in my casserole dish.

Then I add the cheese mixture.
Then I add some more pepper.
Next I add some crushed garlic and some garlic powder
Then I add more slices of cheese on top and some Parmesan cheese.

Next I bake at 350 degrees for 30 minutes.

It was still a bit watery so I guess I could have used less milk.  By the way, here are my other substitutions:

Also I ordered all-purpose flour but it was substituted for Spelt flour due to the shortage.
I had coconut beverage already so used instead of milk.

What modifications to recipes have you tried?