No, not everything. Just the important stuff, as defined by the NLRA. (Various other federal, state and local laws mandate certain things as well.)
That would be an Unfair Labor Practice under the NLRA. Certain things are "Mandatory Subjects of Bargaining" and can not be unilaterally changed mid-contract by UPS.
UPS has signed these contracts with the Teamsters time after time for decades and recommended them to us for ratification.
Also, UPS likes being covered by the NLRA. They are even trying to force FedEx to be covered by it.
[The "country is screwed up" because of decades of bad policies by Liberals, Progressives, Community Organizers and Socialists. Not because of our use of paper towels, water, coffee and other small necessities at work.]