I also use EXWM, and made good experiences with setting keyboard 
remapping options directly in my system's config.scm (via the :options 
of keyboard-layout, which sets XKB options; see the manual for examples: 
https://guix.gnu.org/de/manual/en/html_node/Keyboard-Layout.html).

However, I just use it to remap capslock to escape (for vim/evil-mode), 
so if you need more, I'm not sure if it'll work for you — I've never 
used xmodmap, I'm not sure if you can do everything using XKB options 
that xmodmap can do — at first glance xmodmap seems more general.

~stuebinm

On 18.07.21 16:41, Akib Azmain Turja wrote:
> I have setup my Emacs iwth EXWM.  I am trying to remap several keys to
> avoid repetitive strain injury (RSI), also known as Emacs pinky.  To
> accomplish that, I am using xmodmap.  It works perfectly when I invoke
> the command directly.  However it doesn't work when I put it in Emacs
> startup files.  After several days of research, I discovered that
> xmodmap only works when I have pressed atleast one key in my keyboard.
> Any solutions?
>