i would just put my two weeks in , in your letter you can describe how you want to pursue better opportunities and thank them for the skills and experience, but that’s still a decent way to quit instead of just never showing up ever again, you would be doing it formally.

I just asked my SM if we could talk privately. Then we went outside and I said “I hate to do this bc I love everyone here but I’m putting in my 2 weeks bc I have been offered an awesome opportunity to get my animal career off the ground. And that it was better for my mental health” he hugged me and said we’ll miss you but you do what’s best for you