How much appreciation do you expect to see from today to three years from now when you sell your house?
Based on that appreciation, how much is that $800k house you want to buy selling for today?
How much will you need to save to make up the difference between buying the $800k house today at a lower price with your current equity and three years from now at a higher price with your future equity?
I've thought about this and cannot make the numbers work out in possible hypothetical situations for me. I'm curious what your plans are.