As of TW 20230318, after updating to systemd-253, the file
/etc/X11/xorg.conf.d/00-keyboard.conf
is rewritten with default values on every graphic login, 
discarding saved xkb options.

More precisely, I like to do:

> localectl set-x11-keymap us pc104 '' compose:lwin

These settings are saved in
/etc/X11/xorg.conf.d/00-keyboard.conf:
Section "InputClass"
        Identifier "system-keyboard"
        MatchIsKeyboard "on"
        Option "XkbLayout" "us"
        Option "XkbModel" "pc104"
        Option "XkbOptions" "compose:lwin"
EndSection

as well as (I believe only starting from systemd-253) in
/etc/vconsole.conf:
KEYMAP=us
FONT=eurlatgr.psfu
XKBLAYOUT=us
XKBMODEL=pc104
XKBOPTIONS=compose:lwin

This is all fine. 
Unfortunately upon re-login all those settings are wiped out and replaced with
defaults.

I tried to find out why this happens and I think that 
"display-manager start"      calls
"/usr/etc/X11/xdm/keytable"  calls
"localectl set-keymap us"    which wipes the settings.

I think the behavior of "localectl" changed with systemd-253.

As a possible workaround, the option --no-convert could be used in 
"/usr/etc/X11/xdm/keytable" like this:

> localectl --no-convert set-keymap us

which would avoid the resetting of the xkb* values.