The 2020 NASIC report has a paragraph about solid- vs. liquid-fueled missiles:
The trend in modern missile systems has been toward the use of solid propellants because of their reduced logistical requirements and simplicity of operation. However, some nations have greater access to liquid-propellant technology and continue to develop new liquid-propellant missiles. In addition, liquid-propellant missiles can be more efficient than solid-propellant missiles for very heavy payloads. The missiles with the world’s heaviest payloads, the Russian SS- 18 and Chinese CSS-4, are liquid-propellant ICBMs, and Russia is developing a new heavy-lift, liquid-propellant ICBM called the Sarmat.