P0130, P0135, and P0401 Fault Codes on Skoda Fabia 1.4 (2000 Model) - Cold Start Issues with Engine Stalling and Fuel Smell

Hello, My Skoda Fabia 1.4 (2000 model) is showing three fault codes simultaneously: P0130, P0135, and P0400. These errors occur only during the first cold start of the day — when the engine starts to run roughly between 500rpm and 1100rpm, then suddenly stalls. The vehicle runs smoothly once warmed up. During these stalling episodes, a strong fuel odor is noticeable. I've already taken it to a Skoda service center, but they suggested replacing the EGR valve despite indicating it's not likely the root cause of the issue. Could these three fault codes — P0130 (O2 Sensor Bank 1 Sensor 1), P0135 (O2 Sensor Heater Circuit Malfunction), and P0401 (Insufficient Exhaust Gas Recirculation) — be related? Is there a common underlying cause for this behavior, especially during cold starts? Any insights or recommendations would be greatly appreciated. Thanks in advance! Note: This issue is specific to the 2000 Skoda Fabia 1.4 model with a naturally aspirated engine and early emission control system.