Well, I do not want to sound harsh, but what are you complaining about? That you have not upgraded your MS, your fighters and have not trained your pilots so the game is hard? So why have not you upgraded then? The mission to get a new MS is quite soon in the game. Far before the Precursor portal one...
to Avane: The third MS depends on which route you chose. Besides it is not the best MS in the game
And you get your third MS pretty late in the game, usually just before the end.