For what it's worth, I've shipped hundreds of thousands of dollars of business material (small, expensive electronics, I repair them, so every transaction is a receiving and sending shipment) and I've only had a package lost once, but it was recovered by the postmaster when I called them, he went to the house it was accidentally delivered to and picked it up (they GPS track scans, so if a package is delivered to the wrong house, they can find out). The other few times something was "lost" it was due to scammers or mailbox thieves, completely outside of USPS control.
There's ways to Photoshop an address label to make it show up on tracking, but never arrive at your destination making it possible to ship an empty box to another person and have it say delivered on your end. It's really simple if you understand how their tracking system and scan codes work, people scam Amazon returns all the time that way. It's a common scam, disturbingly easy to do, and hard to prove that you did it.
USPS is also severely understaffed. My carrier is working 2 routes at the moment. My mail used to come around noon, now it's 8-9pm. Need a job anyone?
If you're sending or receiving something that you can't afford to lose, have it insured, and have it shipped express if possible. Never once has an insured, or priority mail package gone missing for me (I've had a few missing letters), and that's out of hundreds / thousands of packages. They also have signature and ID verification services, and to prevent theft, you can have an item held at the post office. For really expensive items, I opt to hold at post office and require ID, same deal if I suspect anything shady.
Also, the tracking process is done somewhat automatedly, one of the postal workers explained how it works. The system knows where the package SHOULD be, and says it is there. Most packages aren't scanned individually during transit, they're scanned in bins, if your package accidentally ends up in the wrong bin, it can be scanned in to a location that it is not. If you call a postmaster, they have access to the actual tracking info, and can find out the last time and real location that package specifically was scanned, attempt to recover the item. Once it's at a local post office, it will be specifically scanned back into the system. USPS postmasters (in my area at least) do take their jobs seriously, and are more than willing to help you track down a missing package. Reviews for the local PO are terrible, they claim that the employees are rude, and unhelpful. However, I've noticed that they respond to your attitude in kind. If you come in all angry blaming them for missing package, they're a lot less likely to help you, the lady at the front desk has absolutely nothing to do with your missing stuff.
If you pay with PayPal friends and family, Venmo, zelle, or cashier's check, you're pretty much screwed. There's a reason PayPal charges a fee, it's to protect you. Bypass the fee, and PayPal doesn't give two hoots.
I've seen a handful of a items I would have loved to purchase here, but I'm not willing to send non-refundable money to a complete stranger before my product is received. I'll happily pay with regular PayPal, or through a CC merchant or escrow service, but I would never use PayPal friends and family, Venmo, or Zelle with someone I don't know personally.
I don't want this to come off as rude, but if you didn't insure your package, and sent money bypassing "the system" than when something goes missing it's on the buyer or seller.