In the past I had a project where the 230V paths had to handle 10A, for this I didn't have better idea than to use the biggest width fit on my schematic (5mm) and make it double sided and connected with VIAs to give a double surface area.
Then at manufacturing I have used the Outer Copper Weight 2oz for max copper area.
Even then when an 1100W load was connected I could feel the device getting hot and if you calculate that:
I=P/U=1100W/230V=4.7A
It is only half of the planned capacity so on 10A this thing couldve burn I never tried.
I'm designing another DC system which has to carry max 10A@12V through some lanes. Of course I could just add additional regular copper wires between the points and it would easily handle that but then what's the point of manufacturing a board I can just protoboard it.
Is there any future for the board making which can produce strong paths like this on the picture:
Brand new interactions and interfaces. 
Easy to use and quick to get started. 
"In the past I had a project where the 230V paths had to handle 10A, for this I didn't have better idea than to use the biggest width fit on my schematic (5mm) and make it double sided and connected with VIAs to give a double surface area."
You were given detailed help about how to handle such a design in this post:
https://easyeda.com/forum/topic/Trace-width-for-10-Amps-8d27666daa37462497f2ec9077b60181
" I could feel the device getting hot and if you calculate that:
I=P/U=1100W/230V=4.7A
It is only half of the planned capacity so on 10A this thing couldve burn I never tried."
Do you mean a semiconductor device or the traces on the PCB?
You have not stated what temperature rise you consider acceptable and you have not given any temperature measurements so it is not clear exactly what "hot" actually means in your design.
You must decide on an acceptable temperature rise and then design for the calculated trace width. The reply to your original post gives several suggestions for how to design connections to and between multilayer copper tracks.
If your tracks are still hotter than the desired temperature rise then the options are to: