Sorry for facing this issue, it's my pleasure to help us.
Welcome to the Shopify community!
and Thanks for your Good question.
Please share your site URL,
So I will check and provide a solution here.
Would you mind sharing a recording or a screenshot of what you see when trying to access your theme editor? If you could share your store link as well, I can take a look for you. To confirm, have you tried using another browser or a private/incognito browsing tab? Let me know if you see the same issue there. Cheers.
Glad to hear that's working for you now. You can find out more about adding store policies in this help doc. Feel free to let me know if you have any questions along the way. Cheers.