Hello and congratulations on the new pair.
I personally would not mess with the ph. I feel a stable ph is always better than an ideal one. The problem I’ve had when messing with ph is fluctuating values and eventually a ph crash.That is very hard on the parents and it will kill both the fry and parents if it drops to low to fast.
I would be patient and try to see if your male is just young ( how old are your fish? I see you’ve had them 11 months but how big were they when you got them), if he is inexperienced and not making good runs, if your cone is in a high current area of the tank etc. I would try and move the cone to an area with lower water flow. If you see them spawn you can turn off your air or your mechanical filter, which ever you are using. You could also try lowering your TDS a little more but I would do so slowly and carefully. In my experience, you are in that sweet spot already at 80 ppm. With my water much softer, the ph drops fast. You could have a lot of calcium in your water and need a little softer water.
As a last resort and you do decide to lower the ph I would use peat moss in your storage container. I have had less ph crashes when I tried peat moss instead of acids. I did lose some fish due to ph crashes early in my attempts at breeding so I gave up on what the books said was needed and just let my ph stay higher and where it was stable. I have had very good hatches at ph of 8.2 and around 80 to 100 ppm so it can be done. That said my source water may have less calcium than yours.
Whatever you decide good luck!
Respectfully, Matt