Wordpress hacking issue problem posts get deleted and plugins too

I have a Wordpress website hosted at Siteground hosting (there we have backup, access to the file manager, database ….) All Posts delete automatically, (they don’t appear on the website nor we can see it on the wordpress control panel). I check at PhpMyadmin and I see that most of the posts are there, but not all of them, so really only some are deleted. In order to find a solution, I did this 3 days ago. 1. Restored website and database from backup 2. reinstalling wordpress 6.1.1 3. I deleted all users except admin and changed its password 4. deleted all plugins 5. I replaced the .htaccess for a clean new one 6. installed Wordfence security plugin 7. Deleted the previous theme (Generic Press) and replaced it for Hello Elementor Theme 8. I activated from Siteground control panel the Site scanner premium service (I scanned and showed no problems), also activated maximum security disabling php uploads, ftp uploads, I placed all the restrictions Today monday again all posts are deleted from Wordpress control panel, but on phpmyadmin I see most of the posts 9. Again I restored a backup in order to recover the posts and plugins 9.1 Note: Before restoration of backup number of rows in posts database rfv_posts: 828, rfv_postmeta: 10927 After restoration of backup number of rows in posts database rfv_posts: 1017, rfv_postmeta: 12362 So this confirms that posts were actually deleted from database 10. I eliminated all plugins and installed site ground security plugin 11. I manually installed wordpress 6.1.1 12. I placed a new .htacces 13. I placed siteground security plugin and placed also 2 factor authenticator and placed maximum restrictions for more security 14. Changed admin password (there are no other users) 15. At site scanner service from Site ground I scanned again and placed maximum security 16. I changed the database password then the same problem happened again posts deleted and plugins deleted it might be sql injection or other issues … I will provide access to the person selected to Siteground Control panel. From there there is direct access to the Wordpress control panel Right now the website is presenting the issue with the plugins deleted and the posts deleted. Once you check this, I can show you how to restore to a backup so you can see it with the plugins and with the posts.