Hi zaskia,
welome to the forum.
Your phals are looking great, looks like they came from a good source.
Phals like these are grown in warm nurseries in jiffy plugs (the dark brown squishy thing in the middle). They retain a good amount of water and dry out at a good rate in a hot greenhouse so are great for phal seedling roots.
Once the roots poke out they are wrapped in spaghnum moss which protects them during shipping. They then arrive in Europe and we buy them.
Now what to do with that jiffy plug. If that plug stays damp for too long the phal will rot at the base. A european climate cannot handle a jiffy plug well unless you know exactly how to water it. The jiffy plug will actually change color quite drastically between wet and dry. When it is wet (which will cause rot) then it is a dark brown color. When it is dry it will look a lot lighter, more like a coconut color.
The problem is in a european climate with moss wrapped around these jiffy plugs they can take up to 3 weeks to dry. That is far too long. The phal will suffer.
So, option 1 is to remove the jiffy plug and pot the plant into some bark.
option 2 is to use fan and heat to help dry the moss but phals don't like much airflow so it needs to be passively blowing away from the phal not directly on it and heat is not that easy to provide but if you don't want to repot it you have to make sure that jiffy plug in the middle turns a coconut brown within a week. If it stays damp for longer than this then the plant will be in serious risk of developing rot.
Aim to water the plant enough that is stays damp for up to a week and then let it dry for a couple of days.
If the substrate does not do this for you then you need to pick something that does work for you. A jiffy plug and moss is not a preferred choice for anyone in europe, that is how they arrive from transport.
If you want to do what is best for these phals, I'd repot them. It will stress them and it is a good idea to let an orchid adjust to its new environment first but if the plants start rotting that is no good so I would not take the risk, jiffy plugs are a real danger in a european climate.
helpful video if you are unsure how to repot:
PS: If you don't have the right pot size or the right substrate yet that is ok! I would still remove the jiffy plug and then just wrap a bit of the moss around the roots till you have everything for a repot. Spray the roots to keep them hydrated when they turn a silvery color.