I tried to create a cake topper when you first posted , (with Affinity Designer, which I just got a couple nights ago to run a test on, and haven’t really gotten conversant with it yet), and i wasn’t able to do it.
Now that could be because, like I said, I’m still unfamiliar with how it works, or it could be because I can’t find a couple of very important functions necessary to design cake toppers. I know it doesn’t have an Auto Trace, and if you want the shape of the topper to follow the flow of the letters, you are going to have a really tough time trying to do it in AD.
So I tried to work around that by merging some path offsets…and that’s where I hit the other wall. The offset path function on AD appears to be tied to the raster side of things, not the vector side, and while I can get a nice glowy looking thing around the text, I can’t turn it into a vector path for cutting.
Third problem…merging overlapping paths cuts a segment out instead of merging them, and unfortunately, I don’t know how to adjust for that yet. So no script fonts.
I’d consider trying out Inkscape for creating your topper, I’m just not sure there’s a way to do it in AD.
But, because I also know that some people swear by it…here’s a link to an AD video for beginners. Maybe you can find something in there that will help you.
YouTube probably has a few others that can tell you how to use the program, or you can check the AD site for tutorials.