Courtroom-friendly flats that can handle long days of walking (and fit in a tiny office stash?)

Quick background: I need shoe recommendations and I want something practical, not precious.

I live in Texas and my days bounce between courthouse runs, office hours, and the occasional client meeting. I end up walking more than I expect - parking, security lines, and racing up stairs because I am inevitably cutting it close. My current 'nice' flats are fine at first but by midafternoon they turn into foot torture.

What I'm looking for:

- Flat or very low heel, since courthouse floors and high heels do not mix

- Polished enough to wear with suits and midi dresses

- Comfortable for lots of walking and standing

- Durable, because I am hard on shoes

- Compact enough that I can stash a backup pair in my office or car without taking up a ton of space

- Bonus if they wipe clean easily and don't show every scuff

Budget is flexible but I tend to be frugal; I'd rather buy one solid pair that lasts than replace cheap ones all the time.

Do you have a go-to pair or style that holds up? Any specific models or brands to look at, and any insole hacks for flats that actually work?