Sorry for the awkwardly-phrase title; I ran up against the character limit.

Anyway, I have a bunch of files that are tagged with details I would rather omit. Here's a screenshot for reference:
PerfectTUNES Screenshot.jpg

Notice the [3] after "Little Willie Leaps" in the highlighted field. I want to delete that without deleting the rest of the filename. In any other piece of macOS software (including dBpoweramp Music Converted, when I'm ripping CDs), I can use the arrow keys to go to the end of the selected text, then just hit backspace a few times. However, if I use the right arrow when I have this text selected, it just takes me to the next field over. Every other piece of software I've ever used would use tab to move to the next field, and tab does indeed work here, but the fact that the arrows are duplicating the tab functionality means that I can't figure out how to edit this text without reaching away from the keyboard to move the mouse and click inside the already-selected field.

The only workaround I've found so far is to copy and paste (using the keyboard shortcuts) inside the field, which then allows the arrows to behave as expected. However, this clears out what was in my clipboard, which is very frustrating when I'm trying to paste something into a bunch of fields, for example.

Basically, I'm wondering if there's a way to use the arrow keys to navigate inside the selected text, and just use tab/shift-tab along with the up/down arrows when I want to navigate between all the fields.

Alternatively, if this has not been changed because users might have arrow-key navigation in their muscle memory, could we perhaps have a modifier key attached to the "normal" arrow behavior (i.e. starting from the screenshot above, the right arrow key navigates to the next field, but command+right arrow would put the cursor at the end of the selected text)?