If you have ever searched for open source keyboards, you might have come across OpenBoard. But that project hasn’t seen development in more than an year. Thankfully, there is a fork of it that is being worked upon quite actively. It already supports autocorrect, glide typing, user-defined dictionaries, multilingual typing and now material you themeing as well.
And even with that… I gave it a shot for a while… But unfortunately, it is nowhere near as good as Google’s swipe/glide typing. I was constantly having to fix words or just not use the swipe typing at all.
Even in closed source keyboards, google one is the most accurate out of all in my experience