Stock heater plate, stock melamine print board support. All 6 screws in, stock springs. Tried to take a picture of the warp in my melamine bed support, but just not good enough light. I assure you it is there though. Note the rear left Brim, it is a bit waved. Important to understand that there is no speed compensation in these -printed @ 50mm/sec- so the filament has to adhere to the bed as it is being twisted around the bend at speed. The other edge has to thin out, the inner edge has to bunch up to go around the bend. I printed this morning, then turned everything off, and it is a nice cool day here. I did not gauge for these, this is just from home and go. I did pre-heat the bed though.
I preheat my bed before gauging it for nozzle height, this is important, the aluminum needs to hit equilibrium to flatten out as it wants to be, at the temp you choose. Your thermistor is just 1 spot on the plate, and it is a surface spot to boot. So pre-heat, then hit print, should give it time to hit it’s sweat spot.
Point…nothing wrong with what you have beyond setup, these things are a labor of love, and reward with great print size and speed. Lots of info out there, on this forum, just gota learn from it.
Hatchbox pla at 205c, plate at 70c, acua net for adhesion. I only use brims for prints with external supports. But being that you put up a picture of yours, I figured it was a good way to counter the negativity. Not saying there have not been some real bent up heating plates out there, I have seen them. But for the most part they are good to go, it’s just a matter of slow heat up. Great machine, just not going to love you for impatience, or half-assed corner cutting