> Some key mappings break in text boxes. I've remapped Find to Control+F, which works most of the time, but not if my cursor is in a text box, because then it moves the cursor forward. Control+B for bold and Control-A for select all are likewise. To make it worse, this only happens for certain text boxes, and heck if I can figure out the pattern.

Don't remap Cmd+<key> shortcuts to Ctrl+<key>. The great thing about the cmd key is that it doesn't conflict with anything else. Ctrl-f is forward, ctrl-b is back, ctrl-a is beginning of line, etc, these have been around in emacs (readline?) for a long time and it's great that native os textboxes implement them. This is why it's inconsistent; bad apps use their own snowflake controls and fail to implement them.

cmd-<key> don't conflict which is why they're used. Ctrl-c meaning both SIGINT and "copy to clipboard" is a disaster on terminals, the cmd-c life is much better. By trying to remap cmd to ctrl you're working against the OS and the OS will fight you back because it's not designed to do that.