It becomes more expensive (2x) to mine Bitcoin (one gets half of the amount for same effort and electricity). And as the miners tend to be the ones selling the bigger amounts of bitcoin (to support their business' expenses, for example), it translates sooner or later into an increase of the price.
Many consider the price of Bitcoin as made of 2 components: the price of mining it and the speculation related extra. I agree to them. This being said, on the long term the ETF may be the one that could reduce the volatility. But that will happen only after some rounds of competition in accumulation (i.e. possibly even wilder volatility for the first 4-years cycle).
But I am no expert, I just express my logic and expectations. I may be right, or I may be wrong. Time will tell.
PS. In the "what's new", it's not just the ETF and halving. I would add as kind of news the ordinals (kind of NFT on Bitcoin blockchain) and COPA vs CSW trial.