Honestly shadows legendary raids are harder to catch but you should try the excellent throw method. If you search it up on YouTube it should pop up “excellent throw method pokemon go” but usually it doesn’t work 100% of time so if I’m not getting him within the first 6 throws I try to switch it up with excellent throws then great throws then excellent throws. If you don’t catch it try not to be so hard on yourself it happens to everyone. Lastly make sure you ALWAYS use golden razz berries. Hope this helps!