The Fenix TK20R V2.0 has a 3000 lumen strobe mode with an instant access button on the tail, but as others have mentioned, I don't know how far that gets you in a self defense situation, especially in daytime. Depends on the actual situation ... up close, it could buy you a few seconds to hit someone upside the head with something, or to take off running, I suppose.
Unlock 3000 lumens of blinding clarity and 56,600 candela with the powerful and reliable Luminus SFT70 LED in the Fenix TK20R V2.0. USB-C charging, dual rear switches, and a maximum visibility range of 1558ft is yours. The included 5000 mAh 21700 battery gives you an amazing 48 hours of runtime...
fenix-store.com
This was going to be my recommendation with a warning
NOT to get the UE variation of this same light, as the 2nd button is replaced by a rotating mechanical switch. Won't get into it, but there's issues with that switch.
Then I would have mentioned how silly it is getting a flashlight for self-defense while relying on the light output itself to stop an attacker. You want self-defense with a flashlight? Get a clip-carried 2AAA penlight with a good grip and a slightly scalloped bezel. Use the flashlight as a hammer-fist enhancer with the bezel protruding out the bottom of your fist. I recommend the Powertac Sabre.
Ironically both the Fenix and the Powertac models mentioned are excellent flashlights in their own regards for use as simply flashlights. With the Powertac being a long-time personal EDC of mine due to its reliability, output, ability to run on not just alkaline batteries. Plus its unique feature of being able to be unscrewed in two spots and then the top and bottom being able to be screwed together without the middle. Thus, turning it into a single-AAA flashlight. Handy in an extreme emergency when the batteries inside the light are dead, and you can only find one working AAA cell.
But yeah, no need for that strobe foolishness. Anyone who doesn't want to use a gun or is legally prohibited from doing so. Get a larger than keychain-sized canister of Pepperspray (not mace), with a carry clip on it; and use that instead.