> really want to generate yield

Treasuries are not the best way to do this. Almost any investment is better than yeeting a substantial portion of your net worth into Treasuries or a savings account.

> really want to preserve capital

Fiat currency, or bonds that promise payouts in fiat currency, are excellent for short-term capital preservation and terrible for long-term capital preservation, as every government that uses fiat currency has succumbed to the temptation to print more of it whenever it seems expedient.

Gold or Bitcoins are far better for preservation of capital.