AT: 1) "experience so many good and bad things" (see UDB) or 2) "suffer so much" persecution because of their original commitment to Christ or 3) "work so hard" to keep the law
AT: 1) "they would have been of no value at all if you had not been trusting in him" (UDB) or 2) assuming the Galatians were working hard to keep the law, "if the work you did were only for nothing," meaning that they were depending on works, not on Christ, and God would not count them as believers.
Paul asks another rhetorical question to remind the Galatians how people receive the Spirit. AT: "he … does not do it by the works of the law; he does it by the hearing with faith." (See: [[rc://en/ta/man/translate/figs-rquestion]].)