There are only two possible explanations for what is going on with Trump’s Postal Service.
(1) All of the disappearing mailboxes and sorting machines are part of routine logistical planning, and
(1)(b) The president’s words about mail-in voting and the Post Office are meaningless and no reasonable person should take them any more seriously than they do his claims to have done more for African-Americans than Abraham Lincoln or that he would build a border wall that would be paid for by Mexico. He’s a child who says whatever comes into his head and no reasonable person should take any of his words as representative of his beliefs, his plans, or his administration’s policies and actions.
(2) Trump repeatedly said he believes mail-in voting will cost him the election. Then the Postal Service suddenly started taking actions that were out of the ordinary. Because the president wanted it to.
As conspiracies go, this isn’t like QAnon. You don’t have to decode anonymous internet posts and do a whole Pepe Silvia thing. It’s pretty straight forward: Trump say mail-in voting bad. Mail has problems. Trump stop mail.