This seems like a very large design oversight in Figma Slides. The help article says that “Published changes only apply to new slide decks that are made with the template.”
Doesn’t this defeat the entire purpose of having a custom template where you can edit a style and have it apply to your entire presentation, instead of needing to manually tweak a header style on every slide? I expected this to work the same way instances update in Figma Design when you make a change to the main component, but even after publishing changes to a custom template in Figma Slides, my existing slide deck that pulls from that template isn’t updating colors & text styles. The published template changes would only apply to brand new slide decks, which means I’d have to define the template first and then create my slide deck.
That completely goes against the general approach to how many of us create slide decks. For example, I don’t make the template before I start the slide deck. I make my slide deck first by letting the content I want define the structure & storytelling and then do a layout/design cleanup pass at the end where I create and standardize some styles. This is the point at which I would find a template useful — at the end of the process. Not at the beginning.