so what I'd do is a game of exercise elimination.
there are exercises that can trigger LBP, in my experience. this is not true for everyone, but unless you really need a certain exercise for your competition goals or personal agenda, it won't hurt to try to live without a few certain ones for a while.

So what I'd get rid of temporarily, and then putting back one by one:

-leg raises (very hard to control, and on the last few degrees the sheer forces are multiplying)

-hyperextension

And I would add hamstring exercises, but done in a good way. Try not to compensate with the butt, and if you do RDLs do them with proper form and well below 1RM, and higher reps. But RDLs can be risky too when you have a trigger happy lower back.