Hi, I use a Lenovo Duet 5 with 8GB of RAM and its ARM chip. I installed the dev environment Debian VM and it works great, any arm64 compatible app I got from Flathub works. But sometimes it seems to crash the entire Chromebook: the screen goes black and then the ChromeOS boot sequence starts and I login to a clean desktop. No idea how to troubleshoot this and whether I can do anything about it. I don't recall it being like this forever and I did disable the (experimental) flag for GPU acceleration a few weeks ago.
I'm not fond of flathub. I find normal sudo apt install is more reliable.
Flatpak can have some permissions which if not granted can cause the app to malfunction. I have never had a flatpak app crash my chromebook BUT I'm using an x64.
I do recall there used to be some special commands required for installing flatpak on chromebook related to allowing nested containers.
The virtualization inherent in chromebook linux environment is another layer beyond what linux typically sees. It seems plausible to me fwiw that could cause big problems if not managed correctly. So I'm in agreement with your suggestion to see if it helps to avoid flatpaks (or else maybe revisit the flatpak installation procedure at the link if it still applies)
Full on crash, I have 4 GB and that never happens. Although sometimes the screen reader completely breaks and I must force restart.
It's hard to say what's causing this for you. It's never happened to me, but I have an Intel processor and I install applications the traditional way using apt/nala.