My Apple Watch will charge but shuts off once it is off the charger

hello Evarga_9, You can check your battery strength on your iWatch. From what you say looks like you need to have it charging. On the iWatch go to Settings > Scroll down to Battery and click > Look for Battery Health and any service recommendation message. If you battery Maximum Capacity is below 80% then you may want to look at getting battery service or replacement.

Batteries - Service and Recycling - Apple