desperate: stuck on apache restart after server configuration changes, getting `address already in use` error!

okay guys, i'm completely stuck here. i was just trying to get my new app's server configuration right, thought i had it all figured out after spending like half the day on it. but now after making a bunch of changes to apache config files for a new virtual host, apache just flat out refuses to restart. every single time i try systemctl restart apache2 or service httpd restart (i'm on ubuntu btw), it spits out 'address already in use: make sure apache is not already running'. but i've checked netstat -tulpn, and nothing, absolutely nothing, is listening on port 80 or 443 that looks like apache. i even went full brute force, tried killall -9 httpd and killall -9 apache2 just in case, and still the same exact error message. my website's totally down, offline, gone.

i'm seriously pulling my hair out over this, clients already on my back asking why their dashboard isn't loading. what in the world am i doing wrong with this server configuration? it feels like there's some phantom process or something. how do i even begin to properly debug this 'address already in use' error when netstat shows nothing? is there some obscure hidden process or another service i'm totally missing that's hogging the ports? please, any ideas would be a lifesaver. anyone faced this before?