Elections can be messed up without knowing party affiliations. What we're seeing in Pennsylvania is more incompetence caused by the cuts that Trump and DeJoy have insisted on, and in ruby red counties, or at least historically so, to boot. When you have 30,000 ballots in one county seemingly lost in the mail and the USPS delays or possible neglect from the same being the most likely cause, then yes, postal workers can affect outcomes without necessarily intending to do so or striking at a particular party.