No charge, completely dead

This is going to be my first attempt at repairing a nintendo switch, but I’m very nifty, so bear with me.
No life at all. I haven’t used it in a couple months or so. When I went to plug it in, it was totally dead. It won’t charge the device nor the joycons, wether on the dock or straight to the console. I’m thinking either bad battery or bad USB-C plug. I don’t know how to diagnose and check these things, but I’m all ears.

Does the dock react if you plug the console into it?

You can take the console apart and check the battery with a multimeter, if it is under 3v it is “too empty” and it might be that the charging chip does not accept it (you can charge it up externally with a charger stolen from a cheapo powerbank)

You can also check the charging chip, it should become 4-5V on a capacitor next to it (should be the one on the bottom near the joycon connector)

No response from the dock. I’ll have to get a multimeter. I’ll keep you posted