Was Germany's WW2 jet aircraft program doomed from start? I heard it somewhere that they never would be able to acquire heat-resistant Metals during the war (to build the engines

Not to take away from your question, but these previous questions can provide some more insight into the jet aircraft plans at the end of the second world war:

Mistakes of the Luftwaffe command during WWII, where /u/Domini_canes states "Germany not only was out-produced in pure numbers, but they were also out-produced relative to their industrial potential."
Why did Hitler ban any notion of a fighter jet being placed in mass production until the close of WW2?, /u/kieslowskifan says "The 262 program ... was beset by technical issues which were compounded by Germany's shortages of strategic materials."
How good was the ME-262 really?, /u/buy_a_pork_bun gives a different view: "Oddly enough, the Germans did actually produce a sizeable amount, approximately 1400 262s."