None of that really matters because the fed doesn’t mark to market, and losses the fed takes doesn’t matter. If anything the current situation means the fed isn’t giving it’s “profit” to the treasury anymore. It can eat losses because the cash account on the fed balance sheet might as well be an infinity symbol.
It’s not a “stealth bailout.” This is the result of the fed owning long maturity assets bought when rates were low, while the fed is now paying higher interest on the overnight bank deposits to keep rates high to control inflation. In 2018 this was predicted to happen if rates needed to be raised (ie to control inflation).
Here is the actual context for that chart
The fed and it’s balance sheet is independent from the treasury and it creates and destroys money at will. Where do you think all that Quantitative Easing money came from? It wasn’t an act of congress to allocate the cash, it wasn’t the treasury issuing bonds. What happens to the money the fed receives when the QE bonds it’s holding mature? If the fed doesn’t reinvest it, that money is effectively removed from the money supply. The fed doesn’t issue anything when it creates currency. It’s all accounting.