Laptop won't start, something possibly blown on it

That symptom usually points to a power rail or protection issue rather than the CPU, especially since charging still works. On Tongfang boards, a split-second power LED often means the EC is alive but the board is failing early power sequencing, commonly due to a shorted MOSFET, bad high-side/low-side pair, blown current sense resistor, or a short on the 19V or 5V/3.3V always-on rails. I would start by checking for shorts to ground on the main rails, verify +3VALW and +5VALW are present and stable, then see if Vcore or GPU rails try to come up before shutting down. Also inspect around the DC-in circuit and battery charging IC, since milk or past liquid damage can cause delayed corrosion even if charging still works. Given your microsoldering skills, this is very fixable, but it will take schematic-level probing rather than part swapping.