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Here's what I would do. BUT you'd better wait for more expert suggestions!
Laser in focusser and on. Loosen all three collimating screws in the spider a turn or maybe two. (Don't touch the centre screw) Reach in and grab hold of the secondary mirror holder and wobble it to move that red dot around to check you can get it on the centre spot. BE CAREFUL that the laser doesn't bounce off the primary, miss the secondary and hit you in the eye - keep your head to one side of the OTA. If you cannot get it on the centre spot, something is grossly wrong. Stop and think and observe the whole topend setup carefully for something out of alignment.
If you can get the red dot closer to the centre spot, hopefully on it, screw the three collimating screws back into place while holding the secondary on the alignment you want. I'm guessing the red dot will wobble around a lot while you are holding the since it is fairly fine changes to the angle of the secondary will move the red dot cm across the primary? But the object here is to convince yourself that the red dot can be made to hit the centre spot. Then, with the three collimating screws touching the secondary mirror holder again, start again from the beginning (sight tube through focusser) since you may have rotated the secondary a little and need to return it to correct alignment, square to the focusser.
Yes, adjusting the three primary mirror screws should have virtually no effect on the position of the laser dot on the primary.
But, I don't have a truss scope, let alone a lightbridge, just a small tube newtonian. I'm just proposing a gross approach for an apparent gross problem.
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