Openboard was good but got abandoned a year-ish ago, but there’s a fork of it now that I’d highly recommend checking out, they have glide typing but you have to manually install it but it’s a really easy install. I switched from gboard and I’ve been using it for about a month or two happily.

https://beehaw.org/comment/1196291 (app in the OP I made but link is to a comment giving instructions for the glide typing)

Archive links in case the link is down: GhostArchive / Archive.ph / Archive.org

Edit: Installing the glide typing makes it partially non-foss because it uses Google’s glide typing library, which is also why it has to be manually installed.