That’s… Not super clear. I’ll try.
The forward voltage of most UV LEDs is high enough (and goes up quickly enough with current) that you can’t get nearly 8A into them from a single Li-Ion cell without a boost driver. I don’t think they’d handle 8A anyway, but that’s the main issue. For this reason, to really make a high-powered UV lamp you’d probably want to go two-cell with a buck driver. There was a guy around here somewhere running a C8F (for three LEDs) with 2x18650 (via an extension tube) and a buck driver.