Change up your equation a bit. The trembling is caused by dt varying slightly (like +/- 0.01), and if you have a multiplier on it, it will tremble like that.
Something like this will help to smooth it out some:
This function was generated on https://www.desmos.com/calculator
Using this equation:
\frac{\left(1\ -\ 0.00001^{\left(x-0.5\right)}\right)}{\left(1\ -\ 0.00001^{2\left(x-0.5\right)}\right)}
That way, when dt fluctuates, it will dampen the visible oscillations rather than amplify them.
So you're equation:
lerp(ScrollX, Player.X-Xcam, dt*speed)
becomes:
lerp(ScrollX, Player.X-Xcam, ((1-(1/(100000*speed))^(dt-0.5))/(1- (1/(100000*speed))^(2*dt-1))) )
Then you can try varying your speed between 1 and 10 or so.