For me, the key is FOSS. I was a keen fan of swiftkey, its word predictions worked great. Then it was bought by a company that I distrust, and when I was forced to choose another, I decided to try to ensure I'd never have to switch again.
A little while after I bailed on swiftkey, the news reports came that it was auto-filling random strangers' credit card numbers; I felt vindicated.
I've got three soft keyboards enabled on my phone, to choose between as needed.
Unexpected Keyboard is my default; it's a perfectly cromulent basic keyboard, that makes all the punctuation, ctrl/fn/esc available for comfy shell work.
When I need to type in non-ascii characters like accented letters, I have AnySoft available. And pwsafe has a soft keyboard in it to let me avoid passing my (exceedingly hard to type, long random) passwords through the clipboard.
I used to have Hacker's Keyboard in the mix, but Unexpected Keyboard has made it unnecessary.
With "Unexpected Keyboard" (from f-droid) it's ok. I've come to expect that there's a basic choice between easy, with GUI, and powerful (like "sort a region of lines"), which is only GUI if you've got a powerful GUI, like plan 9. Otherwise, powerful means keyboard-driven.
When I've got a long, complex edit, I've got a nice, pocket-size, battery-powered folding bluetooth keyboard; combined with the kickstands on my phone cases, it is pretty good.
when I wanted a lemmy app, searching f-droid only pulled up Jerboa, and I remain happy with it.
I use jove (a small, lightweight emacs) within Termux, and M-X filter-region through sort
I'd love one. Preferably the opens-like-a-book style, not the vertical ribbon.
But I don't want to carry around something that costs that much. They're currently priced for someone with way more money.
Iceraven on Android; it's got extensions I use -- notably SingleFile
that the main Firefox doesn't have any more.
I run LineageOS on my Nexus 6, to get ongoing security updates. I also keep one other sacrificial phone running stock android with bootloader locked, so no more security updates, but I don't run anything on it but my banking app, since it's too insecure.
If you skip updates long enough, someone might find a security hole, and if you've skipped the update that fixes it, you'll be able to jailbreak it, install koreader, read epubs without conversion, use the filesystem for ebook organization.
Also, you'll avoid advertisements, which Amazon is now pushing to the homescreens even of kindles that were bought with the extra-cost no-ads option.
I just searched on f-droid, found
BookWyrm (A BookWyrm client for Android.) https://f-droid.org/packages/nl.privacydragon.bookwyrm/
If this comes through, I might no longer need Iceraven (andoid firefox with full addon support, like before they tore it out; I use it for Singlefile)