Redis Object Cache not able to delete old object-cahce.php

While trying to enable a Persistant Object Cache for my website I’ve run into this issue:
Plug-Ins capable of enabling persistant object cache either complain about the existing object-cache.php in the wp-contents folder or promt me that “a foreign object cache drop-in was found”.

Indeed within the plug-ins section under Drop-ins I can find external object cache. Nevertheless I can neither change theese entries nor delete the object-cache.php within the wp-content folder. Two seperate ftp clients can’t do so either.
Firstly I am not the only one ever worked on this website. Don’t know if there is any corrupted legacy.

Secondly I have no clue wich active plugin is in charge for the given drop-ins.
Here is a list of the currentyl installed plugins:
\- **123 Image Resize**
\- **Child Theme Configurator**
\- **Complianz | GDPR/CCPA Cookie Consent**
\- **Contact Form 7**
\- **Easy Google Fonts**
\- **Elementor**
\- **Event Tickets Manager for WooCommerce**
\- **Redis Object Cache** // not active, my choice for the persistant object cache installed by me
\- **SMTP2GO – Email Made Easy**
\- **Visual Footer Credit Remover**
\- **WooCommerce**
\- **Wordfence Security**
\- **Yoast Duplicate Post**
\- **Yoast SEO**

Does anyone have an idea which plugin is responsible for the Drop-Ins and the php file?

Thanks in advance to those ho can advise.

Best!