Nice to have you on the forum. Garter snakes are awesome.
Here's a link to the forum care sheet. Sounds like you've got a good start caring for this snake.
I hope this snake in a very secure tank the cat can't get into again.
This cat may have lost interest for now but a tragedy could still happen.
Cats are notorious garter snake killers. Sorry to hear about the poor dekayis losing their lives.
I hope things turn out well for your new friend. We would love to see a few photos.
Garter Snake Care Sheet - Caresheets