How do you dress for the physical demands of teaching

Am I the only one who thinks teaching is actually being pretty active? We have quite a strict dress code at our school so my clothing options are quite limited.

Between writing on the top of the whiteboard, squatting down to talk to students at their desks, and speed walking/ running across campus on my prep period, I feel like I am almost always on the move. Standard slacks pinch my waist, and woven jackets restrict my shoulders real bad. Plus, my classroom is freezing in the morning and hot in the afternoon.

I recently got a comfy brami on a whim, which stretches like athletic wear but has a matte finish that can get past the dress code easily. I want to completely overhaul my closet to be this kind of stealth activewear, from my jacket, to the tops to bottom, even ideally shoes that look like dress shoes but are comfortable for all day wear.

Does anyone have recommendations for brands or specific fabrics for clothes that actually breathe, don't trap sweat, and that you can move freely all day without looking like a gym teacher? Which is not allowed in my school btw.