You don't really need those keys for that, there are almost always various chords that do that. macOS, in particular, has "Emacs-light" keybindings in most edit fields: Ctrl-A goes to the beginning of a line, Ctrl-E goes to the end, Alt-Backspace erases a word, etc. Of course, if you use Vim-style keys, you use normal mode for all that stuff.

In general though, custom mechanical keyboards have firmware that can be programmed with "layers": hold down a certain key (or toggle) and layers get activated which changes the meanings of keys. This is the way those very minimal keyboards (which doesn't even necessarily have a number row) can work for daily use. If you want the keys badly, just program your firmware appropriately.