Anyways, the easiest way would to be enroll in a US university. Most grad programs in STEM will give you significant financial aid if not completely paid tuition. Another way is just applying for a job with a big international corporation and eventually they'll bring you on board. Yet another way is J1 internship which you can use to do an internship here and see if you can find a full time job (much like OP did). And finally you can always just keep applying for the Green Card lottery every year because you never know, you might get lucky. And the smaller the country you're coming from, the higher the chances of getting selected.

Good luck!