Raspberry Pi Pico 2 doesn't appear when flashed with micropython

[imSarahOwl]

Recently I bought a Pico 2 with the RP2350 from Aliexpress for my micropython project.
After flashing it with micropython, /dev/ttyACM0 simply didn't appear. I've tested it with circuitpython and the pico-examples, and the serial port appears, only with micropython I can't get to the serial port.
dmesg gives me no output, and picotool says MicroPython is flashed
Program Information name: MicroPython version: v1.26.1 features: thread support USB REPL frozen modules: neopixel, dht, ds18x20, onewire, uasyncio, asyncio/stream, asyncio/lock, asyncio/funcs, asyncio/event, asyncio/core, asyncio, _boot_fat, _boot, rp2 binary start: 0x10000000 binary end: 0x1004f4a0 target chip: RP2350 image type: ARM Secure

What could be the issue?

[GitHubsSilverBullet]

What could be the issue?

First and foremost that we have no idea which board exactly.
If I had to hazard a guess, maybe it's using a cheap and slow FLASH chip and the standard Micropython clocks it to fast. A good macro-photo (of the FLASH chip) or the precise type could help.