With active SELinux systemd-firstboot doesn't work:

Fri 2021-07-30 13:54:16 UTC init.scope[1]: Starting First Boot Wizard...
Fri 2021-07-30 13:54:16 UTC systemd-firstboot.service[560]:
systemd-firstboot.service: Failed to set up standard input: Permission denied
Fri 2021-07-30 13:54:16 UTC systemd-firstboot.service[560]:
systemd-firstboot.service: Failed at step STDIN spawning systemd-firstboot:
Permission denied
Fri 2021-07-30 13:54:16 UTC init.scope[1]: systemd-firstboot.service: Main
process exited, code=exited, status=208/STDIN
Fri 2021-07-30 13:54:16 UTC init.scope[1]: systemd-firstboot.service: Failed
with result 'exit-code'.
Fri 2021-07-30 13:54:16 UTC init.scope[1]: Failed to start First Boot Wizard.
Fri 2021-07-30 13:54:16 UTC kernel: audit: type=1400 audit(1627653256.048:3):
avc:  denied  { watch watch_reads } for  pid=560 comm="(irstboot)"
path="/dev/console" dev="devtmpfs" ino=12 scontext=system_u:system_r:init_t:s0
tcontext=system_u:object_r:console_device_t:s0 tclass=chr_file permissive=0