On your device, does the onscreen keyboard work at all in SFOS? As for interaction between physical keyboard and Maliit, I hope somebody will chip in and explain how the layout is setup. Note that in Flatpak solution, we have maliit plugin partially running inside Flatpak and is installed via extension. I presume you did install the extension.

As for suitable apps, it gets asked frequently. I am not going to reply to it as this does not scale - I cannot repeat my replies every time. Instead, I expect that the new users would take time and read few pages back in history. It could be even ten pages, but only that way we can be sure that the developers don't repeat their replies and spend time on it instead of working on the projects.