Likely this is something in the theme.liquid file. Have a look at Older versions when in the theme editor, if you can find a version before the install can probably roll back to that, assuming there are no other customizations you would be undoing or breaking.
Sometimes I use a diff check tool like https://www.diffchecker.com/ to highlight what has changed between the current and version you are thinking of rolling back to, to be safe.
Is your theme paid? Maybe you could ask the theme dev to help.
Otherwise if that is still too hard, you'd probably need to look at getting some help from an expert or on Upwork or something.