@diademjewel We had and continue to have big brother/big boy talks which help a lot. We place a strong emphasis on taking care of things like our bodies, our toys, our home, and each other. We have pets and a garden that we take care of. We emphasize gentle hands and try to call out and appreciate when he is gentle.
At 2.5 yours might be too young but I have also had ours do time outs starting at about 3. It was mainly a way to safely separate them to tend to one first then debrief with the other. I found I have to end play briefly or else he won’t really be discouraged from shoving. We talk about times when someone hit or shoved or grabbed a toy from him and how he felt. If it was an accident then I ask him to think of a way to help baby sister feel better or next time how to make sure we all stay safe (by giving each other space). It’s possible also that yours is just excited and wants to interact with baby. We have tried to encourage gentle or distance based ways to interact like soft hugs or rolling a soft ball to baby rather than rough housing. A hilarious consequence was at one point he was essentially playing fetch with her.
If redirection isn’t working, tap into their fomo. If our toddler is having a hard time playing with baby (because he’s doing something a baby would destroy like trying to build legos) we will take baby to another space, maybe turn on some music, and have a grand time without toddler. Eventually he’ll come in like hey, watcha doing? And enforce a he must play gently or he gets removed from the space rule.
Sorry for the ramble. It’s late and I’m still awake waiting for the toddler to finally fall asleep.
Eta: another thing I noticed, if I give kiddo more “big boy time” like 1-1 dates with mom or dad or special time after baby goes to sleep where he can play big boy toys or something, he’s often gentler with baby and seems happier to embrace a big brother role with her. Especially with dad he will do a bit a rougher play which I think helps scratch an itch of sorts for him.
Eta2: oh! One more thing, I feel like I remember reading somewhere that the perpetrator should be the one leaving the space. So if you pick up baby and move away it may reinforce the behavior unintentionally. It’s one of the reasons we’ve begun to implement time outs. He is not playing safely so he cannot stay in the play space.