Customizing Whonix

I installed Qubes-Whonix because I want to use Whonix.

I have heard that it is best to use Whonix as default without any changes, but the default Whonix lacks fonts and text input in my native language, so I want to install it. And I also want to install ublock in Torbrowser, and save bookmarks.
What kind of danger would I be putting Whonix at by doing this?

What should I take care of to use Whonix safely?

Do you guys really use the default settings?
Especially without adblocker, isn’t it frustrating to use the Internet?


Same as Tor Browser. applies.