QBI is only for trades or businesses. rental property is an issue as to whether its a trade or business or not. realistically, I would find it hard to see a property that is a vacation rental as rising to the level of a trade or business. if you agree that it's not a trade or business enter 0 for QBI. taking a position it is not would likely carry forward to future years. if you treat it as a trade or business and in any year there is a cumulative profit (all years as rental) you would be entitled to the QBI deduction but then you have to enter into Turbotax the 2019 net loss as the QBI loss carryforward. Most likely in 2019 you took the position if was not a trade or business otherwise Turbotax would have carried it forward to 2020
the IRS has issued revenue procedure 2019-38 for safe harbor election. those that meet its criteria attach the election to their returns(every year) and thus they can treat their rental properties as a trade or business without worry that the IRS will say its not. read section .03 in the link provided. nothing requires a taxpayer to use the safe harbor but then if they take the position their rentals are a trade or business, the IRS can successfully challenge based on the facts in each case
https://www.irs.gov/pub/irs-drop/rp-19-38.pdf
