Tradezero u.s there is no avoiding pdt. I think the Fee schedule is different from tradezero outside u.s. And every front end I've ever used has been a piece of shot at some point ( sterling, laser, lightspeed, etc ect) all fantastic products, but all have had their fair share of moments.
To reititirate:
1. Naked selling?
2. Add liquidity only orders as a routing option specifically nsdq