Last time I used termux it didn't work in any profile except the owner profile. I suppose you already know this but just in-case, you now have the terminal app that comes bundled with the OS (enable it via dev options) and you can download a debian vm and use it. This is all 1st class citizen btw (part of the default OS installation) and not 3rd party app/service. However the only downside is, AFAIK, it only supports mounting the Downloads directory inside the VM so only that can be shared with it. If happy with that limitation, you should be able to (mostly?) do anything that can be done in an ARM-debian.