The USPS in Placerville, Ca. is known to have workers steal packages and it is well documented. I’m sure it is more than just that post office too…
My only solution was to get a private mailbox at the UPS store which logs every package received. So when they try to lie and say they delivered I have proof they did not.
Used to happen on about 1 out of 5 packages, but now with the private mail box (PMB) it only happened once and I had documentation proving it was never delivered to the attendant.
Got a replacement from the vender, they shipped via UPS on the replacement!
The UPS store PMB costs me a little of $200 / year
With the return address on package saying “Flipper Zero” it makes the USPS thieving employees know what to grab