Use the surface of object A as the base to scale the pattern on the surface. After scaling, the pattern remains on the surface of object A, but the thickness increases。
[blender file](https://drive.google.com/file/d/1QZ_pfiXmJeXib4AbffR-sdkUVQ1MkDOM/view?usp=drive_link)
Yes to a certain extent, you can use the solidify modifier, and by changing the Offset to a positive 1.00 it will add to the outside of the object without moving the object from its location.
You can only get so much larger with this as it will eventually remove the shape. In this case, you can get approximately another .75m but will keep the shape better at approximately .17m
In edit mode use Alt-S to scale.
This is the Shrink/Fatten tool in the toolbar.
By weird combination of VertexWeightProximity and Shrinkwrap with offset maybe?
Not exactly sure if it works correctly though…
…and then there are always geometry nodes, of course 
Thank you, I just want to increase the thickness and I don’t want it to gain weight
Thank you. If object A is a complex surface, it may encounter difficulties
This may not be very effective
Thank you, it’s a good idea, but could you share the file？
Here you go:
1_proximity.blend (4.4 MB)
All the information is pretty much already in the screenshot above.
Just remember to assign all the vertices to the Vertex Group (probably any weight avlue would do, as it’s going to be overwritten anyway).
Okay, thank you. I’ll give it a try
Hello, can geometric nodes implement it?
Hi.
It should be possible, yes. Or at least something very similar. There are various useful nodes: Geometry Proximity, Raycast, Sample Nearest + Sample Index… You’d need to learn a bit about nodes though - it might not be that simple 
Okay, thank you. It looks a bit difficult.