I could be missing the point re BBUS but my point is you are...

I could be missing the point re BBUS but my point is you are using TA to time your buy in on BBUS. Even if everybody bought into BBUS and there were no sellers it would not drive the price up. Only a fall in US futures would drive the price up. Very different to a stock where this would drive the prices up. Overbought and oversold sort of works on the same principle being oversold would be an exhaustion of sellers and now the buyers are in control of the price. But has above in this scenario unless US Futures drop the price won't move.

if you want to buy based on TA then I would suggest doing it on the S&P500 for a better signal.