MacBook Pro shuts off upon disconnecting charger, works with charger

Got this laptop July 2020, had a beer spill in March 2021 resulting in a keyboard replacement (functioned perfectly after keyboard got replaced) and then one day I just started getting this issue, laptop works flawless while on charge but once charger is removed, it shuts off with no sign of life. SMC reset did not work, took it to a repair shop and they said it’s a motherboard issue and will cost $250 (don’t believe that it is a motherboard issue after this coconut battery result):

Since getting the keyboard replaced, i could hear a sort of “tapping” sound everytime i shook my laptop (assumed it was the battery as the glue had to be removed to replace the keyboard). I slightly suspect that the battery’s connection to the logic board has come undone and that’s why this is occurring, but I’d appreciate any insight.

Thanks in advance!!