If the assessment seems too strict, a careful review of the duration is worthwhile.
If the duration set seems too high in relation to the risk assessment, an appeal addresses precisely this point. Under Section 53 FPG the length of the entry ban must stand in a comprehensible relation to the circumstances relied on. A sweeping or one-sided assessment can be challenged.
Work out which circumstances the authority weighted too heavily and which it passed over. At the same time document your ties in Austria to support proportionality.