I think there is an error concerning the information about supply voltages. At least it's not consistent: microchip has separate websites for ATmega328 and ATmega328p. On the site for the ATmega328p it says: "The device operates between 1.8-5.5 volts". But the datasheet they link on the exact same site says:
"Operating voltage: 2.7V to 5.5V for ...
You have ATmega328P-AU. Classic Uno with DIP socket has ATmega328P-PU. Arduino Uno SMD has Atmega328P-MU.
The automotive versions ATmega328P-15AZ and ATmega328P-15MZ have separate datasheet starting in Revision History with
Creation of the automotive version starting from industrial version
based on the ATmega48P/88P/168P/328P datasheet 8025F-AVR-08/08....
The answer i've accepted is the proper answer for the problem i asked.
However replacing the C runtime requires to attach and maintain a lot of crt.S files oiginally related to the GCC. To avoid this i "slept several times over this prolem" and came out another solution.
After compiling the host application that have to redirect the interrupt calls
1KB is 1024 bytes, not 1000 bytes.
Therefore 32kb = 32768 bytes.
32768-512=32256, which is exactly the value used for upload.maximum_size for the 328p.
4kb=4096 bytes. 32768-4096=28672 which is the value for the 32u4.
I'd also suggest looking into different microprocessors. The Teensy models often have an SD card socket, and the Teensy 4 (especially if they release one with a built-in SD socket) is extremely fast and capable (600MHZ, dual instructions/cycle). That would be far better suited than an Arduino, though you'll still have RAM limits. (Nowhere near 200 megs, but ...
There are SRAM ICs / boards, however, don't expect 100 MB, more like 1 MB (with the pin numbers and connectivity / protocols that an Arduino offers).
With Flash you can get much further, but it can only be written a number of times; not sure if that suits your requirements.
Beyond that, I'm afraid the real problem is in the processing speed. Mixing 100 ...