More than 80% of lawsuits against STRs are trips and falls. The City might have done you a favor in requiring these railings.
The City might also have done you a favor in pointing out the proper placement of smoke alarms and the number you need (four more).
The cost you’re incurring is largely a one-time cost vs recurring annual income.
Complying with the building code and STR regulations is the minimum you’ll want to do to create a safe home for your guests. Look here for more.
If you don’t have commercial liability insurance protection you’ll want to look into that as well.