ENVFS_RESOLVE_ALWAYS=1 only works for entries in the fallback-path option

[SuperSandro2000]

 ▶ ENVFS_RESOLVE_ALWAYS=1 ls -la /usr/bin/env
lr----x--t root root 0 B Thu Jan  1 01:00:00 1970  /usr/bin/env ⇒ /nix/store/mqvnklaf6mzmj7ng13aph5ymkvzpyhn0-fallback-path/env

 ▶ ENVFS_RESOLVE_ALWAYS=1 ls -la /usr/bin/systemd-detect-virt
lsd: /usr/bin/systemd-detect-virt: No such file or directory (os error 2).

 ▶ ENVFS_RESOLVE_ALWAYS=1 ls -la /usr/bin/bash
lsd: /usr/bin/bash: No such file or directory (os error 2).


 ▶ ENVFS_RESOLVE_ALWAYS=1 ls -la /usr/bin/cat
lsd: /usr/bin/cat: No such file or directory (os error 2).


 ▶ ENVFS_RESOLVE_ALWAYS=1 ls -la /usr/bin/sh
lr----x--t root root 0 B Thu Jan  1 01:00:00 1970  /usr/bin/sh ⇒ /nix/store/mqvnklaf6mzmj7ng13aph5ymkvzpyhn0-fallback-path/sh

 ▶ ls /nix/store/mqvnklaf6mzmj7ng13aph5ymkvzpyhn0-fallback-path
 env   login   mount   sh   wslpath

[Mic92]

Can you see the binary you are looking for in xargs -0 -n1 echo < /proc/$$/environ | grep PATH=?

[SuperSandro2000]

 ▶ xargs -0 -n1 echo < /proc/$$/environ | grep ^PATH=
PATH=/run/wrappers/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/usr/lib/wsl/lib:/home/sandro/.nix-profile/bin:/etc/profiles/per-user/sandro/bin:/nix/var/nix/profiles/default/bin:/run/current-system/sw/bin

 ▶ which systemd-detect-virt
/run/current-system/sw/bin/systemd-detect-virt