The lemmy-style spoiler syntax is a huge pain tbh, and very limiting in that for something to be a spoiler, it needs to be a separate paragraph. Adding || in-line spoilers || was one of my first contributions to piefed because I found it so annoying (that won't render as an in-line spoiler on lemmy).
The markdown-parsing library used by piefed supported using the same syntax as telegram/discord, with || spoiler here ||, so that is what I used for the feature even though I prefer the reddit/stack overflow style spoiler syntax better.