Yesterday I was posting a note about a book and though of a slight visual joke. I needed a bit of css animation added and it seems a bit too much to either have it in the customiser or my child theme. It turns out there is a block for that: Blocks CSS: CSS Editor for Gutenberg Blocks.
This plugin just added a field to the more settings area for the block where you can add some css, I’ve used it on the image of the HyperCard icon about to animate it.
I am still not all in on using blocks, but this could be fun.