If you want to hide them you can do it in the activity settings
https://www.mangago.zone/home/accounts/setting/timeline/
But if you want to literally delete them you have to go in each individual manga you have and delete it, the delete button is right by where it says want to read, reading, or already read on a manga
Just make a alt account. Deleting everything is time consuming. But if u still want to just click on All as in "already read (All123). Then interprase of your read list will open then u can locate delete option below your each read. Just delete them one by one
How do I delete my "Want to reads, Current reads, Already reads?" Easily, I kinda want to organize my homepage. Thank you in advance! ٩(๑❛ᴗ❛๑)۶