The way I avoid stressing about this is by realizing that the iPhone camera is still way worse than a real dedicated camera with a large optical path (lens and sensor). If you care about good photos, the Pro Max won't get you that far in the grand scheme of things.
This isn't as generally true as you seem to think it is. There are absolutely a few situations where a mirrorless / DSLR camera is going to run circles around a smartphone camera, but fewer than you might think.
A mirrorless camera may have a wider dynamic range by default, but modern iPhones have incredible Smart HDR capabilities that actually work really well. With a mirrorless, they can do an auto HDR effect using several photos, but it's a much simpler effect, and you can't get RAW photos when using that. The new iPhone 12 will capture RAW photos even when applying Deep Fusion and other advanced techniques, from what they mentioned on stage today.
I'm fairly sure no common mirrorless camera is going to be able to do HDR video at the level that the iPhone 12 will do it.
If Apple or Google would make a mirrorless camera that combined their intelligent camera software with a larger sensor, that would be epic. Right now, there are always trade-offs, no matter which camera you pick.
I've thought about getting a mirrorless camera to have that massive sensor for night photography, and to have the variety of lenses, but it's a lot of money for something substantial to have to carry around, and the difference just isn't what it used to be.
Even if you're printing these photos, an iPhone 12 is going to be able to take a lot of really crisp, excellent photos. With the help of LiDAR, I think the 12 Pro will be able to create a really compelling portrait mode effect that's less glitchy than the current techniques that don't have an accurate depth map instantly available.
Computational photography is a real thing, and it's impressive how much they have made up for the lack of physical space that would be required for a giant sensor.
If you scroll back on this twitter feed, you can see some nice examples of pictures shot on iPhone by various people: https://twitter.com/halidecamera
They're not "nice for a smartphone" pictures. They're just good pictures.
So true, in pre-covid era I traveled with only a cabin luggage for two and had no space for my DSLR + lenses. So while my DSLR had better image quality, actually I enjoyed more taking photos, filtering, editing and sharing them on the spot with my iPhone.
I would never ever go back to shooting with my DSLR on holidays. I did it and it's just painful to carry around whole day. My iPhone does so much more than my DSLR for a fraction the space & weight of one of my lenses ...
Using a proper dslr or mirrorless does make a measurable difference in terms of the depth of focus, aperture, image size, speed, etc. The lenses in the latest iphone can't really compete with a quality camera lens.
However as I mentioned those cameras are not fun to carry around all day unlike my phone. They are bulky and heavy, so I prefer not to use them except in important events or just around the house. And these days phone cameras are getting rather good for the average user's use case like posting to instagram.
