ETF approved - $2000-$3000 in the short term. Continues to clim as more and more money comes in.
ETF declined - $800 within a week. Slow climb from there on until the next hype bubbl
Either way, in the long term BTC has everything it needs to reach $10k so you keep HODLing.
It's about hundred million dollar and not about billion dollars will go to the bitcoin. And $2000 - $3000 really impossible for the bitcoin to reach that range as soon as possible. The declined of ETF will bring the price of bitcoin into above $1000 but not for the below $1000.
Whatever the outcome it will still result positively but it only depends on us on how we will react that situation. If it will be disapproved, weak hands will dump, hence smart people will buy cheap bitcoins as a result. Once there are still people who supports bitcoin, there's no way it will depreciate its value, it will still rise but in the right time, that is why patience is a virtue.