i really feel frustated, i dont know how to solve this.
i was read and use it. this arcticle doesnt help
https://www.high-logic.com/font-editor/fontcreator/tutorials/font-metrics-vertical-line-spacing
the line gap, arent working anymore
also, i do agree on fontgautlet preview, it same in the general software like affinity.
preview on gautlet
preview on affinity
preview on your tools, that its really big different