However, if you see that a physical ETF has been approved, you can certainly expect a good spike in price because then physical bitcoins will be bought from the market by the managing company. It will create fresh fund inflow and increase the demand in the market.
one point remains unclear though. and that is whether these companies have already bought bitcoin to back their proposal or will they only buy when the price goes up? if i am not mistaken ETF proposals suck as that of Winklewoss have already had the backing coins in their pocket so they wouldn't buy after approval. additionally even if they did buy afterwards it shouldn't affect the price since you aim to do the purchase in a way not to affect anything, possibly even buy off-the market or with some shadow orders.
lets not forget that the amount they can buy is fixed and is embedded in the proposal they can not change it. so there wouldn't be an "inflow" of funds. there will be a one time purchase then people will buy the IOUs from them while they have the coins to back it up.
another discussion would be the market reaction in which case the type of ETF wouldn't matter. the market may see the news as positive or a buy signal and start buying hence push the price up as it works with any other positive news.