Never tried Flitz but...
Twenty years ago when I first got mixed up in this straight razor nonsense, I applied toothpaste to the linen side of my DOVO strop.
And it worked. It made my store bought razor shave ready as well as minty fresh.
Now, thanks to SRP, I know better. Now I know about waterstones, barber hones, and diamond pastes. But when they don’t work, the toothpaste does.
A stupid idea that works isn’t stupid.
LG Roy