Themes are so many, and when searching for one is just like being trapped in a jungle.
A good theme have to be beautiful, to be scalable, to be fast, to be secure and maybe also to have frequent updates and support. If you don’t already know it, I’d suggest you to go on the huge website “themeforest.net” where you can find a enormous selection of themes and wordpress snippets and shortcodes for all sort of sites.
Please be aware that hosting with wordpress is always inferior to make your own CMS/Website/Blog!
Now for the advice you are asking:
I can’t know you and your users’s tastes. I’d be oriented about something not too graphical, with good readability and a formal and serious color scheme. When people follow tutorials or in general learn online, they stay at their screens for long periods of time, so clarity, contrast and dark colors can make the visit to your site more enjoyable.
Be aware that many themes are not compatible with the left-to-right (RTL) writing you do in Arabic, so be careful on what you choose and be sure the theme you are going to buy will support 100% RTL!
In conclusion, I can tell you there are some solution out there that pack a theme with a visual builder (like Divi, Elementor or Visual Composer), with the chance for you to buy a theme one time and then modify it with the editor and adapt it for your own needs. I have been a Divi user for some years and I made nice little sites with it. If you want a cheap and more creative solution, theme packs + builder can be what you are searching for!
Please show us your site when it’s done
Enjoy and use Linux!