I'm with you all the way! I hadn't actually thought it before but when I read your comment that your iPhone was your most important computer I realized I agree with that assessment. As much as I love my MacBook Pro it doesn't go everywhere with me but my trusty iPhone 6S+ does. It is ALWAYS in my pocket if it isn't in my hands. If I had to choose between losing my car or losing my iPhone I wouldn't hesitate for a second to say goodbye to my car or even my wallet but if I ever lost my iPhone I would have a mental breakdown for sure! That is why I would upgrade all the way to whatever is the biggest, fastest, most awesome phone Apple makes and know that for me it is a good investment in me because I'm worth it.
Max/Plus form factor is really for minority. If you look at iPhones sales in past, regular iPhones had been sold at least 4x more. There is no way I'm giving up X's form factor with much larger screen. Phone is a phone. Tablet is a tablet. It sounds like you need an iPad with LTE.
I ordered a 256gb Max. I like large phones with great screens and am willing to pay for it. I think it’s great that there are so many choices available now. You can get small, large, OLED, LCD, home button, or not, cheap or expensive. I went away from iPhones for years to the Samsung Note series. Now I am going back for a while for the XS Max. It’s great that there are so many options.