Repair Rich Text Editor on my website

Hello,

I changed text editor on website and it has some problems to fix:
1. Fix image upload system. Images do not upload. Images links are not correct. Sometimes when I try to edit article with new image there is 500 Internal Server Error, sometimes there is just wrong image link.
2. Insert Link create incorrect links for example:
<a href=\"https://my website.pl/\" >Text</a> insted of <a href="https://my website.pl/" >Text</a>
3. Using unusual characters like ellipsis, long dash, bullet points copied from Word etc. cause errors. If possible it should change them to something simple like *.

I have image upload system on my admin section, so it is possible to upload images on my hosting. I just want it on my text editor.

Website is NOT based on well known CMS like Wordpress. It is dedicated website based on Zend framework.
Website is hosted on VPS (tiktalik.com) with CentOS 7.

php version 5.6 and it CAN NOT be changed.

I do not have contact with website creator or hosting providers. You should fix it by yourself.

Here is a test article with incorrect image and link:
https://wspieramrozwoj.pl/artykul/265/