Automated sanitary cabin management system

Good afternoon!
Kramatorsk is in touch...
The situation is that there is a public toilet in the city center, many people want to visit it, and it is currently the most populated city in Donetsk region! But payment is only possible with paper money, specifically with a denomination of 5 UAH. I am attaching a photo of how everything is currently implemented!
And even having these 5 UAH, it is not a fact that you will be able to access the restroom!
I tried to write a technical specification (in any case, it is not without flaws and "exaggeration").
I am an individual who wants to help resolve this situation!
I am counting on your assistance in solving this issue and suggestions for the project!
Thank you!

Preliminary Technical Specification:
General requirements

1.  Architecture: centralized or distributed system based on a microcontroller (for example, ESP32, Raspberry Pi, or industrial controller with Ethernet).
2. Communication: only Ethernet (do not use Wi-Fi).
3. Power supply: mandatory uninterruptible power supply (UPS) for system operation during power outages.

1. Payment system

• Support for payment via NFC and QR code, integration with contactless payments (Google Pay, Apple Pay, bank cards).
• Do not use paper money!
• After successful payment – unlock the electromagnetic lock of the door.

2. Door control

• Control of electromagnetic lock.
• After payment, the door opens, then closes.
• Internal button for exit breaks the lock circuit.
• Location control — no more than 15 minutes. After that, alarm?!

3. Ventilation

• Turn on when a user enters and operate for 15–30 minutes after exit.
• Automatic activation at the beginning of each hour for 5–10 minutes.
• All timings should be adjustable.

4. Lighting

• Turns on when entering.
• Turns off 3–5 minutes after exiting.
• Disabling time is adjustable.

5. User presence control

• Monitoring closed or open door for more than 15 minutes — alarm and notification.

6. Heating and climate control

• Support for temperature +18°C.
• Hysteresis: 1–3°C.
• Ability to configure these parameters.

7. Control display

• Resistive touch screen (already exists).
• Open/close door, service mode, maintenance, possibly other functions...

8. Emergency help button

• This button exists, two units, one meter above ground and another about half a meter.
• When pressed: display message, sound alarm, open door, notify system.
• Engage passersby to provide assistance.

9. PIR motion sensor

• Already exists in the "booth"
• Activity monitoring, possibly duplicating triggers for lighting/ventilation

10. Monitoring and control system

• Integration with Zabbix via MQTT.
• Android app: open door, change mode, view status, graphs, and statistics.
• Possible web version.

11. Attendance tracking and analytics

• Logs: entry/exit times, duration, payment method, alarms.
• Attendance graphs and tables.

12. Additional requirements

• Remote firmware updates.
• Watchdog, error logging.
• All parameters should be configurable.