Relais circuit for doorbell/intercom based on Raspberry Pi/Arduino and Telegram Bot

General information for the business: Conditional "Physician's Circuit" for (semi)smart home.
Description of requirements/functionality: Hi,

I want to use a Raspberry Pi/Arduino and relais in order to let people open the front door of our house via Telegram message and the existing intercom/door buzzer system.

To be more precise, I want to be able to change the behaviour of the intercom to a "physicians' circuit" (in lack of a better term) on command.

A "physician's circuit" connects the door bell to the buzzer. So when someone rings the bell, the door buzzer is triggered (for x seconds) and the door can be opened. The bell should not ring, when the physician's circuit is active, just open the door. However it should of course ring, when the physician's circuit is inactive.

I have 4 wires coming to my apartment: 2 for the bell and 2 for the button of the intercom to manually trigger the door buzzer. (Some more for the intercom, but that won't be needed, I guess.) They run on 12 V.
The physical door opener button on the intercom must still be operative.

In a first step I want to switch between the two modes "regular door bell" and "physician's circuit".
Ideally the setup should have a fallback mode - for when the raspberry pi fails to work - in which the door bell still rings, when the door bell button is pressed.

Once that setup is complete and operational, I would like to be able to send a command (in form of a text message) from my smartphone to activate the physician's circuit for a specific duration (default 30 seconds but can be set for a longer time - in minutes intervals - as well).
For this I don't want to develop an app or a webserver based application but preferrably use a Telegram Bot. Any better suggestions are welcome, but I need an easy way to allow several family members use the system too. The system should be able to reply to the messages.

The result should be:
If I send a (specific) message to a Telegram Bot (like "open door"), the physicians circuit is activated for 30 seconds. I get a message back ("You can open the door for 30 seconds."). When I ress the bell, the door buzzes open (without ringing the bell in the apartment). If the 30 seconds expire, the bell is back to functionning as usual and just rings.
If I send a message like "keep door open 20" the physicians circuit stays active for 20 minutes and returns to "normal" after that.

I would like to split the project into several sub parts:
1: you recommend the specific components, relais etc. needed for the project. I'd prefer things that don't need soldering, but can manage if needed.

2: guide me through the setup of the wiring, GPIO/Breadboard/etc. combined with a simple test code to see if the basic setup is working as intended. (Turn Physician's Circuit on and off and test what happens if the Pi fails). An LED would also help (if not part of the relais anyways) to get a visual feedback of the current state.

3: once that works, develop the code to switch the pi via mobile devices/TelegramBot and the timing

For any questions don't hesitate to get back to me.

Thanks and best,

Simon
Specific technologies required: Raspberry Pi/Arduino, Telegram Bot, Relais,
OS requirements: Linux
Extra notes: