all-in-one-wp-security-and-firewall cannot change captcha or clean uninstall

Hello everyone,
I have found this great plugin for my WordPress pages and I have activated all sorts of features, and by accident, I have chosen V3 instead of V2 for the captcha. Now, I am not able to login to my WordPress page and I cannot change the settings either. I am not very IT-savvy and I was trying to find a solution here in the forum, and I found this post:

https://www.ads-software.com/support/topic/this-site-cant-be-reached-127-0-0-1-refused-to-connect/

I changed the name of the folder all-in-one-wp-security-and-firewall in FTP and I have deleted the code from the .htaccess file. I still cannot do any changes. I can access my page but the only option I get is to activate the plugin again and that leads me to the login page with the captcha. Deleting the whole plugin did not solve the problem either as when I install it again, it gets installed with the same configuration.

For one of my pages where I did not have much content I uninstalled WordPress as a whole and installed it again, but I cannot do it for my other pages as there is too much content..

I am not sure if the code is getting stored in some cached folder that does not get deleted when I delete the plugin itself or why the configuration does not get deleted..

Is there any way to uninstall it and install it again as a clean version? Or where else does the code get stored, where should I delete it from?

I would greatly appreciate help with this as my 5-hour search on the internet and browsing the FTP folders did not help. My hosting provider does not offer such kind of troubleshooting…