Great discussion and learning opportunity here. . .thanks, Una
My (untrained, crop loving) eye says these are too big on you. That's made more obvious because they're a bright color. If you want to stay slouchy, they should be longer, and hopefully would be scrunchable.
If you size down, they'd probably be a bit shorter, trimmer, and have the more professional vibe for your work formal needs.
I agree with the recommendation for a pump or low vamp flat. No straps showing to visually confuse the hem line.
Any reason you went for red instead of traditional work formal color like black or navy?