I do my routine in the bathtub, warm up for 15-20 minutes, submerge after the stretching, after each set of Vjelq/Wjelq for like a minute, and for warming down (like 5 minutes), cant really tell how much of an impact it has but i've never had negative PIs and i guess partly due to reheating, also no diminishing returns in gains (i recall this being a recurrent issue for people going past beginner's routine, correct me if i'm wrong) and the only change in my routine was warming down and reheating around week 15 of the 20 i've been doing PE.