This is such an extreme outlier behavior, nobody is designing products around it. Pretty much everyone who owns a smartphone carries it around everywhere, because why not.
I couldn't understand this for the longest time until I asked my sister, who kept handing her phone to me to hold on to while on a family trip, about this one day. Apparently, a lot of women's clothing doesn't have "usable" pockets (they're tiny or fake...)! And with the size of modern phones, it's actually often quite a nuisance to carry around a phone.
While this may not be OP's situation, I would guess this might be one reason for the proliferation of cellular-enabled smart watches...
Many business people use mac and would love this. Really weired
Though I do like the idea that this is why tethering to my iPhone is so flaky. It isn’t due to bugs, it is because Apple cares about my mobile data bill!
I seldom, if ever, carry my iPhone outside my house. My Apple Watch with cellular is enough for internet connectivity when away from home.
In my perfect world, I could provision my Apple Watch as a standalone device, and I could get a MacBook with an eSIM.