Isn't the USPS a profit-seeking arm of the government?

USPS is run as a financially self-sustaining business wholly owned by the federal government. (So, not for profit, but also not funded by the government.)

For a long time it was in this weird double bind because the federal government mandated generous health insurance for USPS employees, but did not allocate funds for it, because USPS was supposed to provide its own funds to cover all expenses. It looks like new legislation (PSRA) was finally passed in 2022 to move that burden from USPS and onto the OPM.

It wasn't intended to be profitable. It was intended to provide a public service in the national interest. Any funds raised through postage were to hopefully offset the considerable costs, but the considerable costs were in and of themselves seen as a necessary expenditure for a critical responsibility of the federal government, no more or less so than the considerable costs associated with the raising of armies and navies for the defense of the nation.

there might be an argument for it since DeJoy has been trying to run it like amazon ruining rural service

No??? It's an independent bit of the exec branch designed to operate as a public service. You should have learned this in high school civics class

No?