If I was signing on for a $5,000 non-refundable deposit with a long wait I would at least want a written guarantee that the price was fixed and would not increase (other than special equipment I might order at the time of construction).
I have a $2,000 deposit on an
Escape, waiting on notice of build date. If it is not until 2023 the cost will probably increase, leaving me with a choice to go ahead or cancel, receiving all but $250 of deposit back.