I have a Feller EDIZIOdue push-button in use.
This works without any problems. Press push-button to switch light "On" or "Off". Press and hold the push-button to dim the light "up" or "down".
Unfortunately, I can't tell you anything about this yet. Our purchasing department is of course always endeavouring to pick up and offer the products as quickly as possible.
I recommend you ask the question in the Shelly forum. The best thing to do there is to explain what you mean by "digital switching and indicator lamp".
If the switch can also be "switched over" as a push-button (switching state only when pressed on), you can even use the dimming function by setting an additional function for the long push-button action. However, the dimming would then only go brighter or darker, then you would have to switch off again to start at the initial value. Most switches can only switch on and off, so you have to set the Shelly so that a toggle switch is connected and the Shelly switches the dimmer on when the input is on and switches the dimmer off again when the input is off. Ideally, you have a double push-button for the dimmer, then both inputs can be used with a short press to switch on/off and with a long press the brightness changes.
No, that's not possible.
The "stupid" Feller dimmer and the Shelly dimmer do not communicate with each other. That is why a combination of both devices is not possible. Either no Shelly dimmer or you have to remove the Feller dimmer.
If the Shelly dimmer is used, it is the only device that is allowed to influence the voltage in terms of dimming for the corresponding lamp(s).
https://shelly.cloud/knowledge-base/devices/shelly-dimmer-2/
https://shelly.cloud/documents/user_guide/shelly_dimmer_2_multi_language.pdf
As it looks, this is really not the right illustration! The Shelly Dimmer 2 has 5 connections as you say. https://shelly.cloud/knowledge-base/devices/shelly-dimmer-2/ (unfortunately only English). This picture is of the Shelly Dimmer 1 and should be replaced by Digitec :-( ..... embarrassing
...Greetings
If I understood correctly, it can work with the timer, but over time would loose precision as without wifi it can't synchronise with the time server on the internet