The Embed Optimizer plugin works best Optimization Detective is also running. In fact, there are notices on the plugin list table to encourage users to also install Optimization Detective:

However, when activating the Embed Optimizer plugin there is no advice or ability to install Optimization Detective:

This being the case, when activating the Embed Optimizer plugin, we should automatically install Optimization Detective as a soft dependency.

When Optimization Detective is active alongside Embed Optimizer, the relationship between the two is already indicated in the plugin metadata for Optimization Detective:

So users should be able to see why it was installed.