Double-Layer PCB Design Needed

I am looking for an experienced PCB Designer/Hardware Engineer to design a custom power management board for a BLDC fan system with integrated battery backup.
Key Functional Requirements:
Battery System: 4S LiFePO4 (32140 cells, 3.2V nominal). Must include integrated BMS (B-, B1, B2, B3, B+) and a CC/CV charging circuit.
AC Sensing: Use an Optocoupler (e.g., PC817) to sense 220V AC mains from a wall switch.
Automatic Transfer (ATS): When 220V is present, the fan runs on mains and the battery charges. Upon AC failure (while the wall switch is ON), the board must automatically flip a relay to the internal 12V-to-220V inverter.
Terminals: 4-terminal AC block (2 for 220V Input, 2 for Fan Output) + Battery connections.
Inverter Logic: The inverter should stay in "Standby" until triggered by AC loss.
Deliverables:
Complete Schematic and PCB Layout (Gerber, BOM, and Pick-and-Place files).
Component selection for high-voltage isolation (Creepage/Clearance standards).
Thermal management strategy for the inverter MOSFETs.
Required Skills: Power Electronics, AC-DC/DC-AC Conversion, LiFePO4 Charging, KiCad/Altium/EasyEDA.