PCB Design for Industrial ESP32 I/O Controller (4-layer, isolated I/O and RS485)

I need an experienced PCB designer for an industrial controller board used in agricultural automation (greenhouse pumps, valves and sensors). Board summary: - ESP32 module (8 MB flash), USB-C programming - 24 V DC input with fuse, reverse-polarity and surge (TVS) protection - 8 × 24 V low-side outputs for external relay coils - 8 × 24 V opto-isolated inputs (2 with pulse counting up to 1 kHz) - 4 × 4–20 mA analog inputs, 16-bit - 1 × isolated RS485 (Modbus RTU) - Plug-in UART LoRa module (865–867 MHz) - Hardware watchdog, DIP switch, status LEDs - 4-layer, DIN-rail mounting, conformal coating IMPORTANT: Isolation of all field I/O and RS485 from the logic side is compulsory (isolated DC-DC, optocouplers, isolated RS485 transceiver, TVS). A non-isolated prototype already failed in the field. Deliverables: - Schematic (PDF + KiCad source) - PCB layout (KiCad source) and 3D view - Gerber, drill files, BOM with manufacturer part numbers, pick-and-place file - All files and rights belong to the client Payment by milestones: (1) schematic approved, (2) layout approved, (3) final Gerber + BOM. Requirements PDF and block diagram are attached. The detailed design brief (pin map, layout rules, test list) will be shared with the selected designer after an NDA. In your bid please answer: 1. How will you isolate the RS485 and the inputs/outputs? 2. Show 2–3 similar industrial or ESP32 boards you have designed. 3. Your price and time for each milestone. Budget: INR 37500–75000