Hello Steffi,
it's not that simple.
A floor plan is not a house design. A house design in all its components depends on the plot of land with its advantages and disadvantages, as well as the wishes and needs of the clients.
A design for a couple over 60 has different components than a house design for a young family of four.
And the needs of the family of four would probably be met just as well with a floor plan on a narrow city plot as with a completely different floor plan on a large plot in the countryside.
A house design develops in several phases: a trained/studied architect/planner roughly has structural guidelines in mind and usually works structurally from the outside in, meaning: they look at the plot of land and develop a design according to the development plan and the wishes of the clients, always taking all floors and exterior views (and much more) into account during the steps. This is a process that takes longer than one or two evenings.
Of course, some amateurs have acquired half-knowledge or knowledge through their training over the years and thus have more skills to draw a structured plan or sketch with fewer "errors." Nevertheless, there are probably more compromises to be found than if a professional creates a design. Compromises usually always have to be made, but the architect has professional experience in minimizing compromises and presenting them positively again.
Not everyone is an artist of ceramic clay just because they have taken a pottery course. Usually, one is so overwhelmed by one’s unexpected creative design that one thinks it is good, although it is simply a dilettante work for others.
Basics, in my opinion, that come to mind quickly when planning are: efficient use of living space, little traffic area, personal retreat options for every resident, opportunities for development, generous communal rooms, sufficient storage space, regular routines must function without obstacles (e.g. in the kitchen or bathroom).
Furthermore, rooms should be illuminated with sufficient natural light.
Personal wishes can be: impressive entrance hall, door to the garage, wellness bathroom, open kitchen, gallery, children’s bathroom, accessibility, etc. These wishes must then be incorporated within the financial framework. Preferences should be reconsidered as to whether they have only developed through the current living situation.
There are enough house designs and floor plans to find on the internet. All house providers can be googled and have their designs posted online – some more sophisticated, others less.
There are families who manage just fine with the simplest floor plan, others cherish an individual claim – both are understandable. Usually, the price rules. But I have often seen individually built houses that do not differ from standard type houses externally or in the floor plan.
If you browse building magazines, you will see different building types. In "Schöner Wohnen" the cottage house meets the contemporary standards just like the Bauhaus or the renovated settlement house.
Whether one always has to build modern, I doubt.
The best thing is always to go to a professional if you suspect/know/think you have reached your limits.
Regards, Yvonne