What do you think of KDE in terms of looks?

It's about as customizable as it gets and at least in my opinion looks really good out of the box.

Mind that it might be too customizable. It's quite staggering just how many options it has.

Also, KDE is not a distro, it's a desktop environment (which can be installed on pretty much any distro and comes preinstalled on some).
There's currently not necessarily a go-to KDE distro for beginners, so if you want to use it, we might have to look into your options more in detail.

Then a distro, which (again, in my opinion) looks good, is Debian-based and is quite customizable, is Bunsenlabs Linux.
It looks like this out of the box: https://www.bunsenlabs.org/img/frontpage-gallery/hydrogen0.jpg

Bunsenlabs is not a distro that I would normally recommend to new users. It's fairly minimal and in order to customize it properly, you'll need to dig into config files. It just fits your remaining description rather well, and if it really does fit your taste, I assume you can make it work for you.