Import theme settings to child theme

I’ve just created a child theme for a site that didn’t have one. I tried to import the parent theme settings, but it didn’t work. I tried it using the export file and the “import settings from parent theme” feature. The export file didn’t work at all. The import from parent theme feature got it right, say, 90%. However, some settings are still wrong. Do I really have to check each and every setting just to make sure everything is ok? I run the latest version on PHP 7.4 and 512 PHP memory.