Your post shows how little you understand the USPS.
A) It wasn’t the scaling down of the USPS that is what Trump did. He appointed the head of the org, Louis DeJoy, who did a lot of specific acts that slowed down how mail was delivered. He got rid of over 700 high-speed auto-sort machines that were perfectly fine but out of date and then didn’t order new ones. He cut overtime and lowered the opening hours of offices.
B) The only reason the USPS is having financial issues is because the Republicans passed a law (which many Dems also voted for because they are morons and the plan sounded good at first read) that said all pensions had to be pre-funded through death. That means for every person who works there and has a pension, let’s say being paid $500/mo for the rest of their life, will require the USPS to have a fully funded account in the amount of $500/mo x 12 mo x life expectancy. They can’t do like every other company on Earth with a pension and fund it over time either through profits or by an interest bearing account. That crippled the USPS because they had to divert all their profits. Before that they were profitable, but this stifled all growth.
C) Even with that, they finally came back and made $56 billion in PROFIT in 2022. Yes, in 2023 they had a loss of $6 billion, but the profit from 2022 helped them to not scale back.
D) USPS doesn’t make most of their money on first class mail. The majority of their income is from package delivery ($32.4 billion) and from mailing advertisements ($15.9 billion) vs first class mail revenue of $24.5 billion.