Halving will reduce the supply of bitcoin, so it will reduce the price pressure. But in the long term, the effect of halving will be lower.
the pressure reduced will be very low, let's say that right now 50% are dumped, it mean that there will ve $540 of less pressure every day, which is 1/10000 of the marketcap, which is insignificant...
After the next halving, the block reward will be 12.5 bitcoin or 1800 per day. The reduction is 1800 per day, or $0.7 million per day or $262 million per year. That is quite a big number.