It seems to own a smartphone is better than to not own one, but the effect on buying a new phone on your personal happiness and productivity is insanely overrated.
In praise of laptops
It still seems that by far, the ultimate productivity device is still a laptop (MacBook Pro 13 inch touch bar, maxed out, refurbished).
For visual arts, I highly recommend iPad Pro (the normal size one).
In praise of used and refurbished iPhones
Today the iPhone is still the supreme smartphone by far. But perhaps the most economical and pragmatic thing we can do is simply buy 1-2 generation older iPhones (refurbished on Apple store or used) to maximize our “bang for the buck”. Based on my experiences, every new iPhone might only be 5-8% better than the prior generation; not that huge of a difference. Same philosophy goes with buying cars which are 3+ years old to maximize your savings (or buying a used Lamborghini). If you want to buy luxury goods, it never seems to make sense to buy new.