I’ve been thinking of getting my hands on a kit to build a split keeb, so I was wondering if anyone here knows anything about them? How it was to use, recommendations, anything?
I keep hearing about the Lily58 and Corne, I’m honestly not sure what to look for. Also EU shop recommendations would be appreciated!!
Yes you want a split keyboard 
I use a split now for some years and I am totally happy with that.
My daily driver is a CRKBD (Corne) and I love the layout 3x6 +3.
IMHO start using a split is also a good point to minimize your layout.
The guys from keeb.supply are totally cool human beings and they sell keyboards: https://keeb.supply/collections/40-boards
Also Keycapsss is a valid shop: https://keycapsss.com (… but mostly keyboards are rare there 
)
42keebs (https://42keebs.eu/products/kits/) have also a lot of nice split boards.
Let me know if you need more infos - my brain is full of this keyboard stuff 
EDIT:
if you choose a corne you can also use my own layout
NERDBUDE (but it still need some adjustments)
Sick, thanks for the pointers! After looking around, I think I might go for a corne. What do you think of adding one of those rotary encoder knobs? It seems pretty useful to have a scroll wheel on it
it depends. I only have one board with rotary encoder and don`t use it often. At the moment I play around with a special movement-layer where I have keys with mouse-behavior and this works really well but I also know a lot of persons who love the encoders and won’t live without it anymore. Try it out, it doesn’t have to be your last keyboard 
I am a sucker for mechanical keyboards and have 30+ in my collections (most are some I have built myself from scratch or from a kit).
My main keyboards are all split keyboards and my primary are Iris (in a few different variations), Soffle and Lily58. There are pros and cons with all of them, but I do like having 6 columns for each hand.
You will need to learn how to work with layers, but the world is yours, once you learn how to tackle that. This is especially important if you start getting keyboards with fewer keys than normal, as you have to move e.g. your numbers row, F-key row, etc to another layer.
Shops in EU often do not have much on stock, but there are many to choose from:
https://falba.tech/customize-your-keyboard/
https://ergohaven.xyz/keyboards