Looking briefly at your photo I would say the stars are elongated on both the bottom left and right.
You might try rotating the camera 180 degrees. Does the distortion remain on the image in the same location or does it also rotate 180 degrees?
In your test with the laser how are you holding the laser in the focuser? A lot of clamping mechanisms can introduce some tilt for sure. The Baader click lock is quite good to use in this test. I've done this test with my TEC refractors and a few times I was convinced I had a focuser error only to try again with a new mask, different laser clamping tube and eventually prove to myself that all was actually good!
How far off from center is the laser spot and does the location of the spot relative to the normal camera position look like it might be responsible for the distortion? i.e., imagining a compass rose if the spot is off center at 180 degrees one might expect to see distortion on the photo at either 180 or 0 degrees (or both), but perhaps not at 270 or 90.
If your camera has a tilt plate as Greg said previously you can try using that to compensate for the tilt. It's not too easy to do if it means you cannot access the adjustment screws without taking the camera off. CCD Inspector can help with this....the whole thing can start to do your head it that's for sure. If you want to make this easier you might look into this device:
https://www.gerdneumann.net/english/...ting-unit.html
Also, you might be surprised just how many adapters are not well made and introduce tilt and centering off set errors. If you have a dial indicator you might be surprised by what you discover!
Good luck!
Peter