That's actually the "reasonably" part. The BT keyboard mapping is not completely perfect for a few corner cases (I think alt-space was one?). Hackers keyboard is OK for small tasks. You might try a small USB keyboard and USB OTG cable if your phone supports USB peripherals. I used the setup more when I was going someplace and didn't want to drag a laptop. Since I'm not going much of anywhere these days it's of much less use, in fact last time my check termux busted on some update but I haven't needed it so I haven't fixed it.