> Would you agree that buying a camera is worth only if you are willing to do a lot of preparation and post processing but if not just buy a phone with all the advantages it brings?
Yes.
You definitely can get better pictures out of a camera than a phone if you want to put in the time and the work, not just of using a camera instead of a phone, but of learning how to get the most out of a camera. But it is a lot of time and a lot of work, and given the capital investment not something I'd recommend taking on until you've pushed your phone as far as it can go and find you still want to go further.
Too, you mention a baby coming. Not saying this is you, but I've lost count of the guys I've worked with who get all excited with a baby on the way, buy a camera, and knowing I'm a photographer ask lots of questions about how to use it well - then, three months later, they're back to their phones because it turns out "the best camera is the one you have with you" is a cliché because it's true.
Lately most of my work is chasing wasps around with a macro rig, and let me tell you: there is no wild animal on Earth, a baby included, who will wait around for you to set up a shot. They're going to do what they're going to do, and whether you get the shot you want is entirely your problem. If you want to get that shot with a camera, that means not just knowing how to use the camera, but having it at hand and ready to shoot basically all the time. Which you can do! But you've already got your phone with you all the time anyway, you already know how to use it, you already keep its battery charged - and not for nothing, but a phone'll take a lot more abuse than just about any camera ever made, and we're talking about a baby here.
Which brings me back to the point of time. The shots I get (and occasionally post at https://aaron-m.com/topic/images) are the product, not just of hours of effort in capture and post, but also of four years I spent making photography a daily part of my life. I didn't go anywhere without my camera - eventually, my cameras, both the macro and the 200-500mm tele birding rig. I bought a giant backpack specifically because it would fit them both, I took them out with me on breaks at work, I walked all over God's green earth with them looking for good spots and eventually for good insects and spiders - I more or less lived and breathed photography for four solid years, long enough to figure out what I really wanted to do and get pretty damn good at it for an amateur with a full-time job.
I don't say this to brag, but to make clear the point that you want to think about whether that's the kind of time you want to invest, and the kind of time you can invest - with a baby on the way, and with a phone that if we're being honest already does 90+% of what the best DSLR or mirrorless on the planet can do. Sure, I happen to live firmly within the 10% that phones can't match, or at least not yet. Nobody thinks about the macro wildlife photography that I do as a phone camera use case. Taking pictures of babies, though? People in general? That's where phone cameras live. For that, I can't do better, or even as well - I'd have needed to spend those four years doing portrait work instead. (Or human portrait work, anyway...)
So yeah, I'd say save the money and the frustration, and revisit the idea of a DSLR or mirrorless once you can clearly articulate a reason why you might need one. Until then, your phone's going to serve you much better than any discrete camera will.