Hey!
Whether it's possible to write in other languages or not, doesn't depend on the application, but rather on the font face that you would like to use. Most font faces are made to work with Latin letters, not Chinese, Greek, etc. There are plenty of font faces, though, that do work with Chinese characters. You can find them just by googling!
Although Affinity Designer is relatively easy to get the hang of, and super fun to use, I don't think you should buy it just to create posts for your Instagram. Here's why:
Nevertheless, you can still download Affinity Designer for free with their 30-day trial. Try it out, see if you like it :)
Here it is in the App store: https://play.google.com/store/apps/details?id=com.pixelovely.spacewalk.game
No ads or in-game purchases, just made for the pleasure of making a thing. :)
You bet! Another game mother F(watch your profamity)fudging changer:
Paperlike (2 Pieces) for iPad Pro 12.9 Inch - Matte Screen Protector for Drawing, Writing, and Note-taking like on Paper https://www.amazon.com/dp/B08245WJ42/ref=cm_sw_r_awdo_D99QNJK0SS9HRD0ZP9RY
It’s a screen protector that feels like paper when you draw on it. I can’t find the brand I use. But bruhhhh it’s nice. No one can tell you better than just experiencing it.
On the Affinity demos and other people who have actually used it, it seems to be pretty fast. I don't know which hardware that had but specs and features are here:
https://affinity.serif.com/en-us/designer/full-feature-list/
Of course the more than the recommended is better, right!