Draining some water is the only real way to lower cyanuric acid.
Yes, you’ll have to drain and refill part of the pool. No chemical trick or additive will remove CYA. That’s just how it works — stabilizer doesn’t evaporate, doesn’t break down easily, and only leaves via water removal.
You have two practical options:
Partial drain and refill – Drain about a third to half the pool (depending on how high your CYA is), then refill with fresh water. Re-test and repeat if needed. This is the standard advice because it’s cheap and effective.
Reverse osmosis filtration – A service truck can filter your pool water through RO membranes, which removes CYA along with other dissolved solids. It costs a few hundred bucks but saves you from draining. Worth it if water is expensive or you’re on a well.
That’s it. No enzyme product or “CYA reducer” has ever worked reliably in my experience. Don’t waste money on them.
Future you will thank Past you for just pulling out the sump pump.