error code 4SNS/1/40000000:VDOR-17.546
Using data from https://logi.wiki/index.php/Apple_Hardware_Test_(AHT)_and_Apple_Diagnostics_(AD)_Codes &amp; other similar resources, I can see that 4SNS is a sensor error, then VD0R V for voltage, D for direct current, but I don't know which component might be 0R.
I'd say you need a repair shop.
The answers to your other questions will depend on the results of that investigation. On a 10-year-old Macbook I'd be more inclined to think the battery was failing than the charger.