I also have /etc/apt/sources.list.d/devuan.list and its all comments.

there should be /etc/apt/sources.list

what version of ascii are you using? I suspect, less than 2.1 which I'm not familiar with.

Here's a guide on a minimal server install and upgrade to beowulf.

Overview:
1) Install ascii
2) Add basic user security
3) Upgrade to beowulf

Here we go!

1) Install ascii system using: devuan_ascii_2.1_amd64_netinst.iso

At tasksel, choose only openssh-server

I chose openrc as my init system without issue, if you are unsure stick with Sysvinit.

ascii is now installed!

2) Correct basic user security (and add a text editor of your preference)

Switch to root account:

su -

Update apt

root $ apt update

Install sudo and a text editor of your preference. I'm using vim.

root $ apt install sudo vim

Add user account to sudoers

root $ adduser <user> sudo

# test if user can sudo in a new shell, must use a new shell!
# if yes, exit root

lock root account with:

$ sudo passwd -l root

3) Upgrade to beowulf

Update sources to beowulf:

$ vim /etc/apt/sources.list

In vim type:

%s/ascii/beowulf/g

Hit enter and ascii -> beowulf

$ sudo apt update

$ sudo apt dist-upgrade

## if that doesn't work try:

$ sudo apt full-upgrade

Select "Yes" for unattended service restart

This may take some time.. once finish verify the upgrade:

$ cat /etc/devuan_version
beowulf/ceres

Congrats! You've upgraded to beowulf

That leaves the option of an ascii netboot iso and local beowulf apt cache/mirror