Kia Sportage P0234 Code: Turbo Over Boost Issue - How to Diagnose and Fix?

Hi everyone, I recently joined this forum and am impressed by the detailed content. I've owned my 2018 Kia Sportage for 18 months and have been experiencing recurring engine stalling issues since about three months after purchase. I've taken it to several garages multiple times—EGR cleaning and DPF replacement were done, but the problem persists. The orange engine warning light is now consistently on. Using an OBD2 scanner, I'm getting a P0234 diagnostic code: 'Turbocharger Over Boost'. The code appears only under load—typically when driving uphill at low speeds and then attempting to accelerate. The issue seems to trigger during high-demand situations. I'd appreciate any insights or advice on what could be causing this, especially related to the turbo system or boost pressure regulation. Any real-world fixes or diagnostic steps would be greatly helpful. Thanks in advance, Mick