I started with computers and with Linux in 1998, RedHat 6, Knoppix, SysRescCd, DamnSmallLinux, soon got fed up with sudo, what with trying to get to work cdc-acm gprs & usb modem & having to make kernel module etc etc etc.
Up until only some weeks ago I didn't use doas.
I booted, logged in as root, masquerade MAC address, ifup.
Another login as user, startx.
This is a good post, this learning about fake executable.
I hope we hear from zapper how he's getting on.

marvellous

installed seatd (doesn't remove libsystemd0)
purged dummy-logind

works

will repeat with seatd & lightdm (if I can)

I just
permit nopass user as root cmd poweroff args -f
in UXTerm in X
it works

I will replace dummy-logind with vanilla, and do again
I'll be back

Also I use xserver-xorg-legacy /etc/Xwrapper.config
and I don't use a login manager

aaaggghhh!

I use do my doas ifup wlan0 in UXTerm in icewm (ice window manager GUI.)
The tests for zapper I did in console.
My daedalus refractasnapshot boots into console, then on the fly I sort out interfaces sources.list xinit firefox-esr

maybe this identity user groups is another parameter here, I guess so, I just gone a root and a user from netinstall.iso

My guess and it is only a guess is there may be a conflict problem with a log or authentication daemon or something like that.
I would persevere with the docs, look at,
https://github.com/Duncaen/OpenDoas

My ssd and subsequent refractasnapshot is probably as bare bones as possible, I have a ton of shit not installed.

zapper,
I just booted a live as I done, and put in /etc/doas.conf

permit nopass user as root cmd poweroff args -f

logged in as user
doas poweroff -f
It works

Zapper I don't quite get why you're struggling with this, you're a clever fellow.
man doas.conf args

The prescribed result, is a toxic level of mass hysteria for the patient, in this case, the news subscriber.

Maybe Richard Stallman could inform Mozilla that they are being wankers.

On the fly I install firefox-esr then I replace .mozilla with my backed up turn all that shit off settings.
Of course when I network up it pulls in that Pocket shit, which I then have to disable, annoying because it is a waste of energy, time, and money.

For a long time I have found that this happens rather frequently and it is a pain in the backside, so choose a mirror, e.g.,

deb http://devuan.sedf.de/merged daedalus-security main
deb http://devuan.sedf.de/merged daedalus-updates main
deb http://devuan.sedf.de/merged daedalus main

Other pains include not having testing netinstall iso's.

If you've got an Android device, or tried the outstanding Android-x86, I suggest you try Lightning Browser (Mozilla,)
an app I have been using for years, can login to the bank, the lot,
3.2MB (6.3MB installed,) Anthony Restaino acrdevelopment dot org.
Get from apk4fun apkpure dot com.

see if a newer ublock from sid installs