USPS has raised their rates. Senders be advised.

$9.2 billion loss in 2020...hardly sounds like the USPS finished in the black THAT year...
They did. They covered expenses every year. In fact in 2020 the USPS made $71.3 Billion.
The problem with them "losing"money is....
1. There is a retirement prefunding mandate. The USPS is mandated by congress to prefund their retirement plan to OPM to the tune of $5.5 Billion per year. This means they were paying for the retirement plans for people not even born yet.
2. Every year, congress creates a budget. They have other sources for revenue, but the IRS and USPS are #1 and #2 . In 2021 the US budget was $6.8 Trillion.
Now, The IRS income is 3.5 Trillion, a little more than 1/2 of the budget. Congress in 2020, dictated that the USPS contribute $80.5 Billion towards the 2021 budget.
The USPS only made $71.3 Billion. They were $9.2 Billion short of the congressionally stated contribution. (Notice how the math works out?)
Since congress went ahead and spent money they didn't have, the P/O would go in debt and therefore lost money.
The Post Office actually turned a $2 billion increase in revenue last year. Any other business, that would be super, but with the USPS, that's considered a loss.