Oh wow, I learn something new everyday. I never did use anything like that before, that cool. I can see how that would allow somebody to become more efficient.
There is a caveat: The terminal requires ctrl+shift+c and ctrl+shift+v because the controls ctrl+c /v are already hardcoded for another puprose in Xterm - the basis of all terminal emulators.
As far as Clipboard manager- the posts above have addressed.
This may be due to scaling, resolution or which theme you are using. Could you clarify the question (Or provide a screenshot) to detail what you mean by "too sharp"?
In tweaks, you can go to Fonts->Antialiasing->Make your choice from Subpixel (For modern computers), Standard (for a bit old computers), or none. If it does not resolve the issue, try changing your screens resolution from Settings->Displays->Resolution and try lowering your resolution and click 'Keep Changes' button if the resolution is fine for you
I'm not sure I understood the problem correctly, but have you checked the default key binding for copying to clipboard?
The default printscreen key in Zorin 16 doesn't go to clipboard. If I remember right, just pressing that key automatically creates a file in a folder (I don't remember which), stoping you from CTRL+V it to some program.
If that's the issue you are having, you must assign different key binding. Go to Settings and look for keys. I'm not using Zorin right now, so I can't help more, maybe later.
Strange, on Zorin OS 16 PRO, which is basically CORE, if I hit the PRINT SCREEN key, it takes a screenshot. On POP OS 21.04, hitting that same key also takes a screenshot.
The last time that key didn't actually do that for me was way back in Zorin OS 12, and I had to install Gnome Screenshot in order to take a screenshot, but that was ages ago!