If you get a 500 Error after installing BotBanish, do not fear you do not need to re-install SMF to get your site back up and running. BotBanish always creates a backup .htaccess file for this very reason. The backup .htaccess file is in the root folder that has the format .htaccess. with a numeric representation of the date appended to the name. (example .htaccess.1570139364). All that one has to do is to rename the original .htaccess file then rename the backup file to the original .htaccess name. Your site will be up and running so that you can uninstall BotBanish.
It would be very helpful if this happens that you send us your .htaccess file that did not work so that we can correct any issues in the BotBanish process to make BotBanish a better product.