Will I still have to gear down my motor when I use a closed loop stepper instead of a normal one?
My machine will have a GT2 belt with a 20teeth pulley so 40mm per rotation.
I will microstep the motor 10-20 maybe.
Some motor/deiver set like that.

https://www.ebay.de/itm/DE-STOCK-NEMA23-23SSM2440-Closed-Loop-Stepper-motor-2-9N-M-4A-Driver-HBS57-LONGS/263916291272?_trkparms=aid%3D222007%26algo%3DSIM.M BE%26ao%3D1%26asc%3D20180213162448%26meid%3D021b32 cd93cf4e6eb23ae6bc38d664d8%26pid%3D100930%26rk%3D1 %26rkt%3D8%26sd%3D263326838489%26itm%3D26391629127 2&_trksid=p2056116.c100930.m5375

My other option is a nema 23 with a planetary gear 5:1 or 15:1 reduction.
Freies schiff 3 stücke 4-Blei NEMA 23 reduktion getriebe Stepper Motor, Getriebe verhältnis 15:1, 20n. m
https://s.click.aliexpress.com/e/b834MfFE