Midnight Commander (mc) and lftp (using the fish:// protocol) are terminal-mode file managers which can transfer content between local and remote systems. There's also rsync, of course. All are available under Termux.

There's also the dolphin file manager, also terminal-based, which is either directly available or may be installed under pip (Python's package manager), I don't recall which offhand.

I tend to steer first to the first set, but dolphin's impressed me in the past.

All are FS/OSS.

I appreciate your recommendation, and yes there are times when a native Android GUI interface may be more useful. But if you're already flying Termux, full power of a keyboard and text interface may be preferable.

I also strongly agree that F-Droid is a preferable package manager and repository. I avoid the Google Play Store for all but a very small handful of packages (and generally avoid installing apps where at all possible regardless), and access Google Play Store when I do need to use it through the Aurora Store interface (itself installable & upgradable under F-Droid).

After over a quarter-century of experience with the Debian package repos, the experience of the commercially-oriented, surveillance-capitalism-based Android app store remains a very uncomfortable shock and disappointment.