10mm belt and nema 23

Hi guys new here so hello to all,

I'm building DIY laser cutter, and as you now they got no load so can swing the x axis in mm per second,

I used 2 nema 23 That i had from a cnc build I did not use so thought I will use them on here, but I can only set steps to 3200 any lower and they stall bad even if I lower to 3mm second they stall, but looking at other lasers x axis swing looks fast at 300to500 when ingraveing but mine at 800mms looks slow, so I'm thinking if I went for a lower nema23 would speed be bit better, or if I put smaller pulley,

Specs are. 10mm belt, 20 tooth pulley, nema23 3008 1.8 angle, 1.9nm, 4.2 amps wired in parallel 8 wires,

Thanks guys for any info you can give, kev