so if btc etf gets approved people will start shifting to btc, meaning alt prices will go lower
my question would be, its still possible for lower prices if btc etf is approved?
Not exactly, if the ETF gets approved the price of altcoins can go up or down because the price of alts are dependent on the price of Bitcoin. For example any alt costs $6/0.001 btc per piece because the current price of Bitcoin is at $6000. Fast forward to a couple of months later the price of Bitcoin is at $5,000 and the price of the alt you hold is still at 0.001 btc/$5. Not all coins increase at the same time but for the most part they'll increase if the price of Bitcoin will also increase. Anything is possible with alts because they're more volatile than Bitcoin.