The Chart 1. on your right, shows the level of Active HClO in the water with pH level from 4.8 to 8.5 using the above Henderson-Hasselback equation with pKa = 7.53.

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At pH 6.5, the solution can still maintain relatively high active HClO of 91.5%, which can still kill bacterias and viruses (including Covid-19) almost instantly.  However, once pH passes the threshold 6.5, Active HClO percentage decreases exponentially. As an example, if your measured pH of your HClO solution is 7.5, approximate only 50% is HClO and another 50% is sodium hypochlorite (NaClO) commonly known as "bleach".  

 

Please note HClO molecules above pH 6.5 are unstable and tends to dissociate rather quickly after production.

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