Can a baby be too easy, or is something wrong?

We became parents to an awesome baby girl 7 months ago. It’s the absolute best. I realize that what I’m asking here might be unpopular as I know (from consulting Reddit for baby advice) that raising a baby can be especially challenging for so many. Here goes:

Our baby is really easy. Like, hit her birth weight within days, has slept through the night since week 2, barely cries, blah blah. She’s seemingly content. We go out to restaurants and bars with her regularly, hang at the park, ride the subway, fly in planes, etc. she’s always cool. Notably cool, in fact. We didn’t think anything of it because she’s all we really know when it comes to babies. But, lately many friends, family, and even strangers are commenting on it. So it got me questioning if everything is okay.

She’s content, but not super happy, if that makes sense. She smiles, but doesn’t just give them away. She laughs but that’s even more rare. Very few times has she had hearty laughs.

Shes pretty serious. Always observing. Always exploring. She seems to be thinking a lot. She seems bright, but I don’t know - she’s a baby.

She’s crushed some milestones, and seems to be behind on others. She’s can crawl pretty well, sits up, has held her bottle since 2 months. But seems to have taken a break from talking - babbled and blew raspberries at around 3 months, stopped, and just now doing those things again. Definitely makes big yells. Has no interest in peek-a-boo, and seems to have understood object permanence this whole time.

She can definitely hear and responds to her name.

So I guess to boil it all down, she seems happy enough, but doesn’t really get very excited about much, if anything.

Is this normal? Should we be concerned?