Sadly, Android version 8 (Oreo) broke gnuroot Debian (see https://github.com/corbinlc/GNURootDebian/issues/206). It looks like the issue may be "seccomp filtering" which was added in Oreo. This problem was noticed immediately upon the initial release of Oreo, a couple of months ago, and it has not been fixed yet. I get the feeling that gnuroot Debian has fewer people working on it than Termux does. I've used both, and gnuroot Debian seemed to give a more "fully gnu/linux" feeling than Termux does. It felt like a regular changeroot environment. gnuroot Debian has an integrated X11 server, which Termux does not. However, gnuroot Debian is a 32 bit Arm environment, and Termux is 64 bit. Even if you disabled wakelock and wifilock on gnuroot Debian, it still occasionally drained significant battery power even when you weren't running any code with it. Termux doesn't do that. Also, Termux supports setting up scripts that are run whenever the handset is booted, and also can be integrated with Tasker. Termux only supports passwordless ssh logins to the handset; there is no concept of a user account, so you have to copy your public ssh keys onto the handset if you want to allow logins via sshd, and since there's no password then, it's a bit less secure than logging in using sshd under gnuroot Debian.