Android allows you to swap the virtual keyboard. I use unexpected keyboard which is also free software. It's excellent for programming. Before that I used Hacker's Keyboard which has actual arrow keys.

Termux also has a configurable bar at the bottom where you can map any keys you want. I use it for function and arrow keys plus a bunch of common symbols.

Here's an example from my dotfiles:

https://github.com/matheusmoreira/.files/blob/38565320fefb92...

Not sure what you mean by modal keyboard, but there is fully customizable row of keys in termux.

I disabled it, because I use special android keyboard app[0] with a custom layout made from scratch[1]: all common symbols, arrows, esc, ctrl, alt, forward delete, paste and enter gestures etc. etc.

[0] - https://jbak2.ucoz.net/ (yes it's horrible website, but it's free and easy to maintain for the handicapped developer)

[1] - https://github.com/Archargelod/jbak2Templates-Skins

It's the same static keyboard, but navigation is easier as you can swipe to navigate around.