Analog circuits are typically not recommended, since they can really badly waste energy.
Sounds like you're confusing terms like "analog" and "linear"?
Analog or digital has nothing to do with the efficiency of a circuits - digital is just analog driven to the extremes (voltage-vise).
SMPSU's amongst others are analog.
[...] In fact, it looks like you bought the version with a servo attached...servos allow you to just specify their position and off they go, but you have to do it digitally.
Not all servos are R/C servos!
R/C servos has been analog
up until around the last decade or so and can still be used with analog circuitry!
However, the mentioned actuator has not
got a servo motor, but instead a regular DC motor, according to the link.
[...] my best advice would be to get a microcontroller with a Pulse-Width Modulation (PWM) output attached to a motor control board [...]
A microcontroller could
be used, but is not what the OP want, so must be considered gross overkill and a bad solution.
A simple circuit, digital or analog is all that's needed, so please don't scare the OP suggesting a microcontroller solution.