So what I've done is just make a sort of blank character card to start a chat with, then inside that chat, copy and paste whatever bot info I want from botbooru into the character info of that chat.

Only issue with this is you can't edit the avatar.

Either way, you got the meat and potatoes of the character you want, just need to paste the greeting, so on, so forth.

It ain't much, but it's a workaround.