Summary
It is possible to connect 220VAC PIR sensors to the SW input of Shelly devices. However, some PIR sensors may be incompatible, causing issues with the Shelly inputs reading the digital input signal due to the additional current of the PIR sensor that might have.
Note that the SW inputs are part of the same circuit with the power supply of the device.Solution
To resolve these issues, install a 330 kOhm, 2-watt resistor between the PIR sensor’s L' terminal and the SW input of the Shelly device.
This should fix the problem by stabilizing the signal and ensuring proper functionality of the PIR sensor with the Shelly device.