That’s 1.25A and at least 3.75W. With DA1K XHP70.3 R70 that will be roughly 500 lumens, quite enough. Even if we go up to max sustained 1000 lumens (my assumption, based on XHP50.3’s test results) that will need around 3 amps. So, such drain rate won’t cause drastical capacity decline.
Also with a fresh battery those currents will be 25% lower.
EDIT: For example I tested LG M52VT with 2.5A discharge current and got 5150 mAh at 2.5V cutoff.