Linux

I would use something Fedora-based. It's just a personal choice from myself, since it's reliable and very up to date. By using a modern distro, you increase the chance your hardware will perform better.

Workstation: uses Gnome, which can utilize the great trackpad
KDE spin: as you wanted KDE
Atomic (preferably uBlue, but Silverblue or Kionite would be great too): my favourite, maybe you could test too. You can install the KDE version first, and if you dislike it, you can rebase easily to the Gnome or whatever version without reinstalling

What maybe won't work is the WiFi and some keyboard things from what I've heart, but you can test it for yourself

I think Pop OS might work on that model, and if it does, I would highly recommend it, as the DE is very similar to macOS. If I recall correctly, that distro also has multitouch trackpad functions that behave similar to those on the MacBook.

Fedora on a MacBook Pro from 2012 works like a charm.

Mint, Ubuntu have all pretty much worked out of the box for me

If you want to install linux because it doesn't support the newest mac os version i would recommend opencore patcher. I use it on my 2013 Macbook pro and it works perfectly fine on ventura(mac os 13) and should work fine on mac os 14

+1 for Fedora. I have Nobara on my 2012 mb and it rocks. Nobara is Fedora but with all the codecs and Audio/video stuff preinstalled.

I've tried a few on my 2008ish macbook pro and they all work. Antix and MX work well as do the others. I know MX gets some hate on here, but it works. I did cheat and shoved an old SSD in there because it really sped things up.

Fedora

Fedora's my personal preference. They have a KDE spin

I've run both Opensuse Leap and Nixos with good luck. As someone else mentioned, it really just boils down to the wifi adapter being shit... But that aside, everyrhing else seemed to work well for me with leap and nix.

I got Arch on one, works like a charm. You need to install one driver for the wifi though.

Not sure if you can jusf run anything on a macbook, but maybe Feren os is worth a try

whatever distro you choose, disable the nvidia graphics first. you'll lose the display out but you'll gain a cooler laptop with better autonomy. integrated graphics is more than enough to drive Plasma.

I have mine running Proxmox to act as a VM server I access from other devices thru the home network.

~~I have a 2013 MacBook running Ubuntu. I would recommend Kubuntu because idk which wifi chip your MacBook has but it probably won't play nice with Linux (which is apple drivers fault). And there is a great guide on how to fix it for Ubuntu

~~

Basically anything should work, I had one for a while running Arch + KDE. Wifi doesn't work out of the box (thanks Broadcom), but once you install the right driver it's perfectly fine.

Debian.

Zorin OS has a really good MacOS themed variant last I heard