Something I noticed is a lot of people draw Maria and Shadow together and I love it they are cute and sad. And I only play the adventure games and have knowledge of the shadow 05 game but Shadow lost his memories (basically die fulfilling Marias wish) after sa2 and I know newer things still has shadow remembering Maria I did see a tiktok that talked about this. But Shadows, personality, and convictions he has come from shadow 05 where he acknowledges that he can't be the same Shadow from before and who he is has his own volition to choose and not hang on to the past. Shadow chose to let the past go and just be him, not defined by other people and his past. I get the whole grief isn't linear, you don't just move on, but shadow was never sure who he was in sa2 as well, he was only doing what others told him to do, or what others like Maria would want him to do. His actions he took in sa2 was what everyone else would want him to do, and he didn't make his own choice. He saved the world because that was Maria's last wish. "Everyone is always telling shadow who he is and what he should do" (Pariah695) as well at the end of the game he says "adiĆ³s shadow the hedgehog" tossing a photo of maria, the dr and him over his shoulder. He's letting the past of who he was go. One way I see it as is when someone you love dies that person you were with them dies, you could never be that person again as you were with them maybe get close but it's never going to be that same. You can move on and acknowledge that you are never the same person as you were then.
I just think this is what makes him an interesting character.