Reconfigured my system with the patch above.

I tested it with the swaylock built with pam support:

--8<---------------cut here---------------start------------->8---
(define-public swaylock
  (package
    (name "swaylock")
    (version "1.6")
    (source
     (origin
       (method git-fetch)
       (uri (git-reference
             (url "https://github.com/swaywm/swaylock")
             (commit "5150d3869cd801cb2badb3c645fa41c01bbfbbbf")))
       (file-name (git-file-name name version))
       (sha256
        (base32 "16n389w5hx8f8dqnhzjgimxmaw648cnnmifazx6zwx2v5vhxa38r"))))
    (build-system meson-build-system)
    (inputs (list cairo gdk-pixbuf libxkbcommon
                  linux-pam
                  wayland))
    (native-inputs (list pango pkg-config scdoc wayland-protocols))
    (home-page "https://github.com/swaywm/sway")
    (synopsis "Screen locking utility for Wayland compositors")
    (description "Swaylock is a screen locking utility for Wayland compositors.")
    (license license:expat)))
--8<---------------cut here---------------end--------------->8---

and following system service:
--8<---------------cut here---------------start------------->8---
(simple-service
 'sway-add-swaylock-pam
 pam-root-service-type
 (list
  (unix-pam-service "swaylock")))
--8<---------------cut here---------------end--------------->8---

I'll make a patch for swaylock separately, when this ticket will be
resolved.

-- 
Best regards,
Andrew Tropin