Code error + changes do not reflect

[CollegeApex]

I just took over a website from someone, upon opening Oxygen editor I get this error (uncaught typeError: cannot redefine property:)

I have seen a similar issue in this thread, however, I cannot perform the plugin conflict check due to the fact that the plugin section does not exist in the menu bar on the left in WordPress, and if there is a way to add it, I do not know how. I don't know if this issue is the reason why the website is only showing any changes made only in my editing browser, other browsers including other devices do not see the changes I have made on the website, I have tried clearing the cache and even used other browsers and devices which never visited the website before. Thanks for any help in advance.

edit:
I have realised I do not have full access to WordPress and will be speaking to a user who has full access, hopefully I will be able to get full access if that is technically possible, then do a plugin conflict check. 🤕

6/4/2023:
I have gained full access and was able to solve my issue with changes not reflecting, it was simply due to clearing the cache with "Purge Everything" button, but the error is still there :)