Well, In Corel Draw the commonly known feature in Illustrator called Clip Mask is called Power Clip.
You put any vector object or raster image inside of it and you can scale it down because it is now inside the container. I use it for a lot of things, but lets put an example using it as a vector mask.
The objects inside will effectively scale with the parent object. You can edit the container nodes as any object. Moving the nodes of let's say a rectangle to make it narrower does not affect the proportion of the element inside.
I almost never squish or squash a power clip. This would deform the content, but you can always copy and re-paste it inside again. It takes you 1.5 s.
Are there tools, or workflows to effectively do responsive web-design in CorelDraw?
Well, yes, you can even export a Corel Draw file with some extent as a web page, but as a personal note, I consider myself with good knowledge about web design, and I would not export a file from either Corel Draw, nor InDesign, nor Photoshop directly and consider that as "web design". You would export the assets as separated elements and assemble them using either Html and CSS code or some framework or platform.
Ideally you define the responsiveness using some CSS like img {width:100%;} of the container.
:)
But err.... now it's exceptionally broad.:)