If wish you good luck of course, but just be aware that building the phone — that’s the easy part: sales, support and the software — that’s a lot of “stuff” that costs significant money — an expense that continues past the shipping of the actual device.
There are two ways to win in the phone business- market share/volume or profit per unit. You are also competing against established manufacturers with essentially a barely-deferentiated product and, given your margins, customer acquisition is going to be very, very tough.
If it were me, I’d work on a completely new OS — I’d build an entirely new thing rather than just something marginally different — and ostensibly, marginally better. A generic phone with a different flavor of Android — do you really want to go up against the Samsung’s and Huawei’s?
No disrespect intended — I hope you succeed!
My wife uses the moto G Play. <150USD for a perfectly functional phone, and frankly I'd even call it "far from minimal," (it has features that many flagships unfortunately don't support any more, e.g. sd cards, removable batteries, and headphone jacks) and for years have looked for an even more commodity platform myself since I have no need for apps or beefy hardware. (GPS, text, html only browser, email, with barely enough horsepower to run the above + a beefy battery would be the pipedream, and sounds _not too far_ from the brick phones I used ~20 years back)
As I told a coworker when I saw this post: Either our expectations of "minimal" or the english language has gotten entirely out of wack, because 350 pounds for a smartphone is so far from minimal as to be laughable. Maybe a "minimal flagship" (and this is where I'm inclined to think the gap between your view on this and mine is, where you said 'if you find good specs cheaper'. Perhaps my view on "good" is a much lower bar, but I'm perfectly happy with my 60$, 5 year old Lumia, and find it to be _far more minimal_, while directly challenging your "break down sooner or later" assertion; I've had droid flagships that didn't last as long.)
The mental dissonance came for me simply from my perception of the word "minimal;" I have a wonderful moment of "Oh man someone's finally making the phone I wish I could buy" whenever I see a thread with this or similar verbiage, then the sad realization that I'm apparently too far to the 'throw out everything but your matress' side of minimal.
I was simply surprised to have not seen other feedback along this vein, and moreso when the other commenter was going grey for advocating what I thought were some good examples of models in that range.
Anyway, I'd want to cap this with a friendly "good luck"; Don't take my jaded disappointment as anything more than the whinging of someone tilting at the windmills of eternally larger and more expensive phones. (Although if you DO ever get the chance to advocate for a truly bare-bones-minimalism in a future product, here's a hearty nudge nudge from this curmudgeon.)