Senior Hardware Engineer Needed for Power Management Forensic Review (75W Boost, USB-PD, BQ Charger)

I am an electronics engineer seeking a highly experienced "second set of eyes" to conduct a focused, forensic review of a custom power management and charging PCB. The board is fully assembled via PCBA using genuine LCSC components. The schematic strictly adheres to the manufacturers' datasheet guidelines and typical applications. However, we are experiencing critical failures across the board regarding PD negotiation, battery charging, and extreme thermal phenomena at partial loads. Core System Components: * Input PD Controller: CH224K (Configured for 15V sink) * Battery Charger: BQ25792 (Buck-Boost, charging a 2S Li-ion pack) * Boost Converter: TPS61288 (Targeting 15V @ 5A / 75W output) * Output PD Controller: IP6520T (30W PPS) intended to charge external devices. * Buck Converters: TPS563200 (5V and 3.3V) * MCU: STM32G030 * BMS: HY2120 + HY2213 What I Have Already Validated: Please note that I have already accounted for the fundamental hardware physics. For instance, the 3.3uH inductor has an Isat of 19.4A, and the output MLCCs are 1210 packages to mitigate DC Bias derating. I am not looking for basic schematic checks. The Issues to Investigate: 1. Input PD Negotiation Failure: The CH224K is correctly configured via a hardware resistor to request 15V, but it continuously fails negotiation and only outputs a default 5V on the VBUS line. 2. Zero Charging & Dead System (No Battery): The BQ25792 is not charging the battery at all. Furthermore, if the battery is removed and only the charger is connected, the board does not power up (VSYS remains at 0V despite VBUS_IN receiving 5V). 3. Output Power Capping & Extreme Thermals: The TPS61288 boost converter is designed to comfortably deliver 75W. Our product is intended to charge external devices at ~20W-30W via the IP6520T. However, when connected to a smartphone capable of 45W charging, the output power inexplicably caps at exactly 25W. Worse, at this minimal 25W load, the TPS61288 rapidly reaches over 100C and enters thermal shutdown. Deliverables Required (Consultation & Proposals Only): * NO CAD WORK REQUIRED: I will implement all changes myself in my own CAD tool. * A precise, engineering-level analysis pointing out the exact schematic or layout flaws causing the CH224K negotiation failure, the BQ25792 power-path failure, and the TPS61288 thermal runaway. * Specific mathematical or layout-level proposed solutions (e.g., recalculating the compensation R/C values, identifying missing pull-ups/downs, or altering specific ground pours/vias). Requirements: * You must be an expert in SMPS physics, control loop theory, USB-PD protocols, and high-power density thermal layouts. * Entry-level or generic advice will not be accepted. * Please start your proposal with the word "Loop-Stability" so I know you have the technical depth required for this review.