No, the Shelly Plus 2PM, Shelly Pro 2PM, and Shelly Pro Dual Cover do not natively support adjusting the opening angle of Venetian blinds. These devices can control the up-and-down movement of the blinds, but they do not have the built-in functionality to fine-tune the angle of the slats.
However, with advanced scripting, it may be possible to achieve this functionality through alternative methods.