Could you share graphs of your room response? Frequency and waterfall? Also, more pictures would be helpful.
Which Focal sub do you have?
A membrane absorber or Helmholtz resonator could help at 40 Hz, but it won't do anything for your dip at 80 Hz. A sub-facing parametric EQ could achieve the same results, but it's best to fix an acoustic problem in the acoustic domain.
If you use broadband absorption, it will help with the 40 Hz peak, the 40 Hz resonance, the 80 Hz dip, and any general bass resonance. If you have a lot of low frequency resonance, that would be a good place to start. But you'll have to build bigger and deeper to gain effectiveness. (That's where the membrane absorbers come in handy, since they don't need to be as deep.)
If I were you, I'd build 24"x24"x33" super chunk bass traps in as many of the vertical corners as you can. The smaller corner traps you have now could be repurposed for ceiling/wall corners. Then see if you have room for two or four 2'x4'x6" traps elsewhere in your room.
If you still have an issues on the very low end after adding more broadband absorption, then you could precision treat with a Helmholtz resonator or a membrane absorber.