Harness disables tortie

lol but seriously i am a first time cat owner. Her previous owners let her go outside and I see her want / need to go but I worry too much. I live in an apartment complex with what I call the “cat gang” outside that I feel like might hurt her and my apartment sits roughly 200 feet away from a major highway. I even take her outside with the vest on and she just lays in the same position and will not move. Am I doing something wrong?? I definitely know it is not too tight, nor pinching her fur. Ps you just know she hates me in the second pic for even putting it on her just to try it out 😅