As the tittle say, i'm searching a rigid aluminum fork to put on my 27.5 mtb.

so on internet i found these options:
https://es.aliexpress.com/item/2014-MOSSO-hard-fork-FK-M5-disc-brake-mountain-bike-26er-27-5er-29er-general-fork/32508226080.html
https://es.aliexpress.com/item/PASAK-bicicleta-duro-tenedor-26-27-5-29-de-monta-a-de-aluminio-mtb-bicicleta-de/32932517450.html

All options i found don't provide detailed measurement, except one (pasak), but it seems strange to me that all sellers are offering rigid forks as one which fits all tyre sizes.

in order to verify if it's possible to fit these, i measured the distance between the wheel axle and the bottom of the headset in my actual setup: 500 mm. with the info provided by pasak fork, i estimated that distance as 475 mm.

i think this difference is important to consider, so i ask you:
-how to estimate geometry changes in the bike before purchasing?
-do you know another seller with better fork measurement?
-do you know a rigid aluminum fork with 27.5 specific dimensions?
-in case of buying pasak fork, is there any method to correct the axle-to-headset distance?