Unfortunately there's no way to set this per-site, at least in Chrome. Similarly, if you disable animations in Windows, you also disable all animations and transitions in websites that support prefers-reduced-motion, causing some sites to feel janky as a result.
They really need to add a per-site toggle for that, and a browser-level option to ignore the OS' setting. Turning off animations in Word shouldn't turn them off in Google Calendar.
Chrome: command line switch:
--force-prefers-reduced-motion --force-prefers-no-reduced-motion