it won't happen that quickly. Inflation will still be around 2 to 3% next year. And interest rates don't drop immediately once the 2% target is reached...
Even if inflation is only 3% y/y, the new price level remains "forever." Prices by definition are not allowed to fall back to, for example, 2020 levels – that would be deflation, and before that happens, the money printing machine will be turned on again. What previously increased by 9% – for example from 100 to 109 euros – will now cost 112 € (3% inflation).
Construction costs in certain details may become cheaper again, but will never reach the old levels. The remaining loss of wealth must be made up over years through wage increases. Otherwise, purchasing power remains permanently reduced.