No you do lose a lot
By filing an I-140, you prima facie document your "immigrant intent",
which would, most likely, be a valid ground for subsequent denials of F-1 renewal as a Ph.D student, J-1 that you may need as a postdoc etc. after Ph.D, as well as their dependent F-2s and J-2s, very
likely TN (if applicable) and B-1/2 as well. Think before you jump.