I strongly suggest trying to use a power block and leaving it charging for a few hours even if you have to borrow one.
Sometimes consoles that have run out of battery need leaving on charge for a while before they will give any indication of power on, this is evident through experience with a Switch I've left without battery for a substansial amount of time (about 9+ months, I know it's not good for them ahah).
if the battery has been drained, then using a PC USB port will charge the console slowly, but will supply nowhere near as much wattage to get it powered up again in quick time. It may not even provide the power to get it past that turn on threshold due to the battery management system in the console.
I'm only guessing since I'm not sure how the Vita's power is managed but I doubt the plugin caused the issue.