It is important to know what driver you are using.
To be compatible with button controller application driver must support *button family of capabilities. ShellyPlus.groovy has no support for button controller application interaction. ShellyPlusPro-xPM has this feature (each input spawns corresponding child device with support for single-, double-, tripple-, long-push. The mapping can be found here Shelly Device Handlers for Hubitat - #516 by dmitry.rozovik).
