Yes of course we have bechira in everything we do, what Rav Dessler says is that the when a person grows his battles are according to his level for instance R’ Moshe Feinsteins battle wasn’t whether or not to be mechallel shabbos. Its really based on a chazal “Kol hagadol mechaveiro yitzro godol heimenu”
Without bechira there’s no purpose in life on this world. Its our choices we make every day that decides what type of olam ha’emes we’ll have.