Since no one has suggested a better solution to my question I'm currently trying to include a custom component into a standard layout using a visual force page.
I was able to create the VFP and add it to my standard layout.
The problem that came up now is the following:
When opening the page which have my VFP embedded I'm able to see it correctly:
The 42$ and stuff there are my VFP page.
But when I'm trying to create that object (so a modal open and I have to fill in the field) the embedded VFP is not showing:
Is there a way to make that Embedded VFP visible and accessible during the creation of my record?
And will I be able to retrieve the value (of that specific VPF embedded element) from an apex trigger in some way?
Thanks for your time!