Since iOS 14, UIAccessibilityCustomAction has an initialiser that accepts an image, as well as a name and action handler. Configuring one will make your custom actions easier to spot in the Switch Control menu.

https://developer.apple.com/documentation/uikit/uiaccessibilitycustomaction/init(name:image:actionhandler:)

Two switch control menus for a tweet. One shows how it would look without passing an image for an action. iOS by default creates an icon with the first letter of the action, in capitals. If there are more than one action that start with the same letter, the next one will be shown with the second letter, in non-capitals. For example, Reply is represented with R, but Retweet is represented with e. The second menu shows each one of the options with an icon, so they're easier to spot in a menu with lots of options. The code used is the same UIAccessibilityCustomAction initialiser, but one of them passes an image, as well as a name and an action handler block.