constance velocity

In my FPS game; I find the position of the player like here:

posX = self._tempPosX + Move.speed*task.time*cos(radian+direct)
posY = self._tempPosY + Move.speed* task.time*sin(radian+direct)

self._tempPosX and self._tempPosY is the point that i use as reference position before player press the moving buttons

The problem is “when the player need to turn left and right” I need to solve the problem using complex (for me) vector, then I feel stuned,
but its okay.

Second, when is use collisionPusher (use the check if the player hit another object), the result is the worse.

because I do not know when they collid and the collision after collid

last, I think that will be better if i use frequently update using

dx = dx + speedx
dy = dy + speedy

but I am not sure that the possition of the player will depend on the computer performance or not and your answer is yes!!!

so, what can I do??? sure!!!

thank you