I see that right now VBTLX yields 2.87% versus 2.37% in the Federal Money Market sweep account (US government bonds/bills/things maturing within 3 months). Also the earnings yield on the S&P500 is 6.5% (current earnings/price+most recent inflation). It makes lots of sense to bet against the mediocre expected 6.5% +/-8% (after 10 years) stock returns with bonds, and against mediocre expected bond returns with cash. Make those types of choices enough, and you will find yourself with less money. So yes, keep 20% bonds, 5% cash, and maybe 10% "real assets" because you actually don't know what will happen. But don't kid yourself: you, reading this, would not know the difference between a high interest and a low interest rate even if you saw them side by side on a computer screen, at the same time, 1 inch apart. Because it is only high or low relative to what interest rates will do over the next 5/10/20 years and you would be lucky to predict that better than a me flipping a coin.
I am surprised to see some people have money at Ally. That means opening and minding an entire new account to get 0.17% less yield than Vanguard's sweep account!
Conventional wisdom says individual investors are just fine directly buying savings bonds, treasury bonds, treasury TIPS, treasury STRIPS, brokered CDs, and direct bank CD's. Fidelity will even let you set up an automatically rolling ladder of many of those for free. Corporate and municipals bonds require loads of research and a ton of money for diversification, so use funds for those (unless you are doing the research and have loads of money).
If you have a date when you need money, buy CDs or treasuries maturing just before then, or choose funds with durations around that time and switch to progressively shorter ones as it comes close. If you don't have a date in mind, matching the market's duration and yield (hint: market fund!) seem like a good place to start. Maybe longer duration if still working, shorter if not working but that is really getting into the weeds.