You can use a smaller font for the label. And you can use a smaller base tile size for your dashboard and then increase the dimensions of each of your ‘normal’ tiles. This give you a lot more flexibility with sizing and placement of tiles and let’s you have extra small tiles for things like labels and spacers.
You could probably do this with the Custom CSS if you’re just looking for a single small label for a dashboard and you don’t want to use the above options.
I’m aware of how AT tileset labels look, but if you’re still looking to share a photo, you can just paste an image in when you are drafting a response on a computer or you can tap the image upload button in the bottom right when drafting a reply.