Hi,
with correct excitation the torque is about linear to current.
But you need to choose the correct phase angle, too.
The torque may be about independent of speed. You should find the max. torque information in the motor datasheet.
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But all this are basics for BLDC control. There are many ways to achieve BLDC control.
I think a froum isn´t the right place to learn all the basics. A forum can´t replace a school.
My recommednation: Read books. Additionally there will be a lot of tutorials often as youtube videos....
And you need to do a lot of math. You need the correct hardware you need the correct software. You need to decide the regulation loop.
For us, who want to help, there are a lot of questions about your application.
Klaus