So is Minexbank doing its job with keeping the price within a 5% daily change range from now on or is that still not a thing? (Im just asking because if that was the case, Id sell my coins for $26 and buy again at $21...)
I think you need to re-read the white paper carefully.
Minexbank purpose is not to lock the price within 5% around $20, but to TRY to limit the volatility by limiting the variation around +/-5% compared to the previous day. It could go up to $100 or down to $0, not a problem either way, Minexbank is not here to keep it at $20.
Right now, there's no point in trying to contain the volatility as the demand is too high anyway, but I guess it's a good exercise to calibrate the algorithm to make it able to cope with such a situation later.