Problem rotating camera using quaternions

I'm trying to make a pseudo backup camera (basically placing freeroam camera behind the vehicle and pointing downwards). It sort of works but the camera seems to rotate really weirdly and I'm not sure what I'm doing wrong. When I draw the vector out before converting it back to a quaternion, it seems to be pointing exactly where I want it no matter the orientation of the car. But after conversion, it doesn't work really well, especially when the roll and pitch values aren't zero.

Here's a video of the problem and thanks in advance for the help!

Code:

local veh = be:getPlayerVehicle(0)
if veh == nil then return end

local veh_vel = vec3(veh.obj:getVelocity())
  
local carPos = vec3(veh:getSpawnWorldOOBBRearPoint())
local carDir = vec3(veh.obj:getDirectionVector()):normalized()
local carDirUp = vec3(veh.obj:getDirectionVectorUp()):normalized()
local carDirRight = carDir:cross(carDirUp):normalized()
  
--Fixes lag of carPos
carPos = carPos + veh_vel * dt
  
--Set reverse cam little bit higher
local camPos = carPos + vec3(0,0,0.25)

--Rotate camera around car's right direction vector (cross product between fwd dir and up dir) 45 degrees downwards
local quatRot = quatFromAxisAngle(carDirRight, -reverse_cam_downwards_angle * math.pi / 180.0)

local camRot = quatRot * -carDir
  
--Draws direction vector of where cam faces
debugDrawer:drawLine((camPos):toPoint3F(), (camPos + camRot):toPoint3F(), ColorF(0,1,0,1)) 
debugDrawer:setLastZTest(false)
  
camRot = quatFromDir(camRot, carDirUp)
  
--Set camera to rear of car
setCameraPosRot(camPos.x,camPos.y,camPos.z,camRot.x,camRot.y,camRot.z,camRot.w)

 

If no one knows why, I think it's because it doesn't allow you to apply a roll on the camera.

 

Yeah I tried using the relative camera mode but I can't seem to position the camera and rotate it using commands. But I think I could just make a custom camera mode using some of the relative camera code to make it work.