Apache on OSX: "not running" and "already in use" for all processes?

OS: macOS Mojave 10.14.6
HTTP Server: Apache 2.4.55

When trying to restart apache server, I get "Address already in use..." message. Hm, so there must be a process that listens to that port, right? With this line (from elsewhere) in Terminal to see what's up:

ps auxw | grep  httpd

it gives

_www              1317   0.0  0.1  4361716   7452   ??  S    12:39AM   0:00.10 /usr/sbin/httpd -D FOREGROUND
_www              1303   0.0  0.1  4361716   7364   ??  S    12:39AM   0:00.23 /usr/sbin/httpd -D FOREGROUND
root               104   0.0  0.1  4359628   5956   ??  Ss   12:20AM   0:01.07 /usr/sbin/httpd -D FOREGROUND
ausername         7671   0.0  0.0  4277256    804 s003  S+   12:21PM   0:00.00 grep httpd
_www              7654   0.0  0.0  4359604   1004   ??  S    12:21PM   0:00.00 /usr/sbin/httpd -D FOREGROUND

Right, so now I try to stop it

httpd -k stop

which gives

httpd (no pid file) not running

Ok, then I try with

/usr/sbin/httpd -k stop
httpd (pid 104?) not running

Hm... maybe:

apachectl -k stop
httpd (no pid file) not running

So what is running then? And how do I restart it? This is the first time I'm dealing with this kind of errors regarding Apache on OSX.

I've checked this thread but nothing worked for me. Using grep -ri listen /etc/apache2 I've got a list of multiple Listen: 80 however all of them where in httpd.conf files with .bak, .original, ~previous, .pre-update. All except for one being used for httpd. How do I know? httpd -V which gives:

-D APR_HAS_SENDFILE
 -D APR_HAS_MMAP
 -D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
 -D APR_USE_SYSVSEM_SERIALIZE
 -D APR_USE_PTHREAD_SERIALIZE
 -D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
 -D APR_HAS_OTHER_CHILD
 -D AP_HAVE_RELIABLE_PIPED_LOGS
 -D DYNAMIC_MODULE_LIMIT=256
 -D HTTPD_ROOT="/opt/local"
 -D SUEXEC_BIN="/opt/local/bin/suexec"
 -D DEFAULT_PIDLOG="var/run/apache2/httpd.pid"
 -D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
 -D DEFAULT_ERRORLOG="logs/error_log"
 -D AP_TYPES_CONFIG_FILE="etc/apache2/mime.types"
 -D SERVER_CONFIG_FILE="etc/apache2/httpd.conf"

and that last file has these lines:

Listen 8080
Listen 80

So now I am out of ideas.

PS: After digging in the logs, this now is a telling sign that I have multiple Apache installations (probably leftovers from Homebrew installations). These two lines:

[Fri Feb 17 00:22:56.067511 2023] [mpm_prefork:notice] [pid 104] AH00163: Apache/2.4.46 (Unix) PHP/7.3.33 LibreSSL/2.5.5 configured -- resuming normal operations
[Fri Feb 17 00:22:56.067613 2023] [core:notice] [pid 104] AH00094: Command line: '/usr/sbin/httpd -D FOREGROUND'

First line says it is running Apache/2.4.46 but it is not the version I get when I run httpd -v The second line seems to log the starting command for the Apache process. Where could this command line possibly be located? Has to do with startup process, right?