The older Nordic SDK wasn't too bad (once you get over the learning curve). Trying to start a project from scratch is challenging though, so much easier to pick the closest example, get that going and modify from there.
However, they've deprecated the old SDK [0] in favour of Zephyr [1] and quite a number of people struggle with it (check the forums and general internet). I have less experience with Zephyr, but both of them use a lot of python support tools which seem to suffer from versioning amd compatibility problems (even trying to keep a stable platform has been difficult here, what works one time doesn't work a few months later). YMMV.
[0] https://docs.nordicsemi.com/bundle/sdk_nrf5_v17.1.0/page/ind...