Toddler tantrums

Im here seeking advice. I have a 4 yr old daughter that when she was two hardly had a temper tantrum. Fast-forward to now I have a 2 1/2 year-old girl who has the most outrageous temper tantrums I mean, throwing herself on the floor won’t get up at one point she tries to like run away from me if we’re out in public it seems to always be over possessions or things that i cannot give her. Before i had kids when I used to see kids throw themselves on the floor I used to have such judgment and now I feel like I give props to the parents dealing with it. After she has her temper tantrum ill either wait for her to calm down and try to talk about it. It’s screaming that really drives me crazy. I’ve noticed it’s anything about not getting her way. Most people say that they’ll grow out of it. I’m really trying to be consistent with waiting for her to stop getting on her level telling her we are not doing that, and we also have been trying time out. Has anyone gone through this? I feel like I’m beyond stressed out and sometimes I feel like I don’t have a handle on any of this!!