I switched to DDG about a year ago and it works fine for me. For some queries, Google still surfaces better results, but DDG is good enough that I don't really miss it.

The only Google service I haven't been able to replace is YouTube - no real alternative. I still use Google Maps as well, but could probably switch to Apple maps without missing much. For hiking trails, Apple Maps has often been superior. I briefly tried OpenStreetMaps years ago, but the lack of traffic data and the fact that it gave me bad directions made it untenable.