I think Unix (not just BSD, but I include BSD-based SunOS 4.x) documentation from the mid 90's was the best and easiest to follow.
The main thing I miss from that era is that practically everything I wanted to know could be looked up in man pages; and if not on that first man page I tried, in a meaningful see-also page.
These days, seems most software (not just Linux, but for any platform) is scattered amongst HTML-urls that point to long-gone former websites, and youtube tutorial videos.
Now you might say that much of today's software is too complex to describe in a man page --- but IMHO - that's the bigger problem. If people write complex monolithic bloat, writing pretty documentation for it is the least of our problems.