I haven't dealt with USPS regarding a claim, however my experiences have indicated more of a supervisory/employee problem that results in inconsistent results. For example we made two mail order purchases from the same store. One on March 2 the other on March 6. the packages were soft envelopes of nearly the same size and weight. The March 2 sent from Chatsworth (CA) to Santa Clarita(CA) a dist center, it spent the night and went to Los Angeles on 3/3, where it spent two nights, on 3/6 it departed for Spokane (WA) where it a night, arriving in Wenatchee (WA) on 3/7. After spending the night it went to Leavenworth and was delivered on 3/8. Travel time 6 days
Package two left Chatsworth on to Santa Clarita and departed for Spokane all on 3/6, arrived Spokane 3/8 then 3/9 on to Wenatchee and Leavenworth for Delivery. Travel 3 days.
We have several packages with similar results. the main issue seems to be if from Santa Clarita it is sent north and all things go well, or if it returns to Los Angeles and all sorts of delays and misdirects occur. One occasion a package went from Santa Clarita back to LA, then to Las Vegas, Boise and Spokane. Travel on that one was about 10 days.
so while we get very good service from our local post office and generally from the other processing centers it does appear that there is a problem in the Los Angeles center for packages being delayed and misdirected. So my conclusion is as noted, there is a problem at the local level of the various problem areas that isn't, to use the current "woke" word, "systemic".