Not cutting in straight line

Check the guides, tension etc

damaged teeth on one side not cutting evenly so the good teeth on the other side allows the blade to veer away from a straight cut
Have the blade resharpened

Here's an old dude trick that might help.
Safety first! UNPLUG THE SAW.
- Take a framing square and set it against the fence. It should be flush with the fence on both sides of the blade. If not, slide the square to one side and pull the blade down into full cut position, then slide the square against the blade and fence to check for square. If square, slacken the bolts on the other half of the fence and align it with the correct side.
- A bit of messing about should have it lined up just fine.
- If it is off vertically, there should be some alignment possible.
Patience and safety.
You'll get it.

I'm not sure if you have a chop saw or circular saw. Either way, it sounds like the nut and washer are not tight enough to hold the blade. If you have a circular saw clockwise will tighten the nut and washer onto the blade and hold it in place. Most chop saws are a left hand thread and then you would turn the nut counter clockwise to hold the blade tighter. The blade wobbles because it is not tight.

If you have a bridge saw. The blade and motor may not be parallel with the rails the motor travels on.

I don't know why they even provide edge guides with jig saws, they don't work worth a flip. The problem is that, unlike a circular saw, the direction of cut is unlikely to be 90 degrees from the direction of the mounted edge guide. The blade mounting is not made to ensure that the blade is held exactly straight. When you follow a straight line with your cut you will see that the body of the saw will probably crab a bit sideways like a car that badly needs a wheel alignment. I suppose the edge guide can work on 1/4 inch plywood with an aggressive blade, but that will give you a very rough cut. Much better to draw the line and just follow it visually. If you need to do a lot of this, and you want a nice straight line, use a circular saw. Good luck.

If you have removed the blade, check to make sure that you have assembled it correctly. All the spacers in the right place.

Tension the blade so it's correct tension.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/craig_3fa289bf857b1a3c

this is usually caused by a dull blade or you need to carefully re-adjust the blade guides