Help! Baby won’t take me seriously 😫

My LO is just a few weeks away from his 1st birthday & I cannot seem to get him to understand the word “no” or when he’s done something wrong. He always thinks I’m just playing a game! I think I have a pretty good “mom voice” & have never had an issue with other LOs this way. I try to limit my use of “no” to safety concerns (since my LO try’s to get into everything I still use it more than I’d like!) and always keep a straight face. Or make a sad (but not goofy) face and say that his actions are making mommy sad. But he will literally just laugh at me every time and try to get past me & back to whatever he was doing. I’m really consistent on the things that are “no’s” and redirect every time.

I know that I am not a very empathetic person so idk if maybe he has a harder time deciphering facial emotions. My husband thinks it’s sweet because all he knows is love & play so he just can’t fathom us having a different emotion. But I feel like I have to do something different so my kid doesn’t laugh in my face every time I say “no”.

He also is pretty advanced in motor skills, but has been slower on his verbal. I know he’s still little, but what can I do?