Kvantum is one of the first package i install on a new install. Most big theme provide a ‘kvantum theme’ for it and if like tinkering there a lots of parameters.
For latte dock, hard to say, never use it. All i know about it:
People that like dock seem to really like it.
Some people report bugs some say its perfect. So like always better try yourself haha
Its unmaintained ATM. KDE is considered to be the actual maintainer but the truth is: no one really want to work on it. A bit sad if you ask me.