There is a very small chance of getting 3M EQM in 2 years. There are some FT members who get several hundred thousand UA EQM each year but I've never seen someone get 1.5M. If you fly business and get 1.5 EQM for each actual flown mile you would still need to fly 2700+ miles each day for 2 years!
Also you can't count on a 2x/3x EQM promo - there's no guarantee if/when this will happen.
If you go forward with this I would look at TPAC/TATL trips since they offer the most miles for your time.
Welcome to FT!