Which is it best: grouping 6 rentals as a "real estate enterprise" or choosing Safe Harbor for each property individually?

I have 6 rentals.  Regarding Safe Harbor, should I choose:  I elect to use a safe harbor for this property on it's own (IRS Notice 2019-07)

or

I elect to combine this property with other properties as a part of a "real estate enterprise" (Revenue Procedure 2019-38)?

Is there an advantage to choose individually or to group the 6 rentals?  Our rentals are investments and not a business.  Thanks