You can install Termux from the F-droid store, which is a Android terminal emulator and Linux environment.
Then install the proot-distro package and you can install stuff like Ubuntu, Debian, Arch...
As OP said, you use Termux. You can use AnLinux or Andronix for easier setup with Termux. You will likely also need a VNC Viewer to actually see and use the desktop. It's been a while, so I don't recall exactly how to do it, sorry.