>>21544244
Found your problem. You're gonna have a hard time doing non-pan pizzas at 250C, and a sheetpan is actually probably hurting your cook. If you can afford it, get a cheap cordierite stone. They have 'em on amazon or wherever for like $25.
I use a ½" steel in an oven that goes up to 550°F (≈288°C). Picrel is a recent pizza I did.