I tried this month on a Samsung Flip 3 and my time was around 4 hours.
A lot of proper androids have roughly the same loading times as iphones these days. Even some lower end devices. My Motorola edge 20 has the same 3 second loadtimes as my ipad does.Not many devices get better times than 2,5 to 3 second inbetween fights.
Will samsung s21 work?