404 error at wp-admin login page

Hello, I recently became a manager at my company after graduating with a MIS degree. I preface this to say my main responsibility is management and I am in no way an expert when it comes to website design nor IT. Bit of a newb, but I welcome any help ??

So, my problem is that I can not get to the wp-admin page at our website, and thus can not make any changes to the website.

I continually get 404 error when using accessing wp-admin page.

I took over this web page and did not build it, as you can see the version is behind.

Things i have tried-

using ftp inside of c-panel file manager and renaming themes folder to themes-old
then trying to access wp-admin

using file manager and renaming plugins folder plugins-old
then trying to access wp-admin

using filezilla to change all files permissions within wp-content, wp-admin, and wp-includes to 0755

making local copy of htaccess file within public_html then straight up deleting it within ftp and attempting to access wp-admin

all these things have not worked, it’s possible i did them incorrectly so feel free to point out something I did wrong in these attempts.

Thank you to all who try to help!

The page I need help with: [log in to see the link]