Reverted Multisite robots.txt issue

Hi,

A while back I thought a multisite would be a good solution for the webshops I was creating, however, during the set-up process I discovered I really disliked the way it functioned, so I stopped. I didn’t go past Step 3 or Step 4, regarding the creation of the network.

I tried to revert the changes as much as possible, such as :
define( ‘WP_ALLOW_MULTISITE’, false);
define( ‘MULTISITE’, false );

However, ever since I attempted the multisite, my robots.txt has been a mess. It has gotten stuck on User-agent: * Disallow: /
I deactivated all plugins and moved to the standard theme: the issue stayed.
I’ve deleted the robots.txt file I had uploaded at the root, and uploaded it again: the system ignores it.
I’ve used the following function to reset the dynamic robots.txt, and I’ve used the robots_txt filter to try and reset the robots.txt: it only changes /?robots=1 and not /robots.txt.

remove_action( 'do_robots', 'do_robots' );

I’ve also checked whether in Settings -> Reading the Search engine visibility was set properly, and it is.
Sidenote: I have made sure to check the robots.txt page after every change, and I made sure to check them in different browsers and in incognito mode as well, as to make sure it weren’t just my cookies. All caches have been flushed too, to prevent any caching issues with it.

I’m at a loss. The temporary ‘true’ settings of WP_ALLOW_MULTISITE and “MULTISITE” has changed something beyond what I can see, and I would really like to know if anyone knows where it has altered the settings for robots.txt. I’m currently strapped for time and I’m not quite at liberty to do a full reset of the website.