Styles (theme colors) don’t allow selecting RGBA/HSLA

It seems like it’s impossible to set RGBA or HSLA in the “Styles” menu where global colors can be configured. The “A” part is requried to make some colors transparent, like you do for tag colors, borders, and dividers. Is there any chance you can add this or am I missing some other way than using a child theme or editing theme.json directly (which I guess is a bad idea)?