And even though there weren't very many 286 protected-mode OSes there were still several of them, with the OS museum including:
1B/V3 (a Japanese OS with an object-oriented desktop and extensive compound document support, part of the TRON project) Microport SysV/AT Prologue TwinServer (an obscure French OS that originated on 8080/Z80) Multiple versions of OS/2 1.x QNX 2.21 QNX 4.0 IBM PC XENIX
1B and TwinServer are especially notable since they were maintained as 286 OSes long after x86-32 machines had made 286 machines completely obsolete; the last versions apparently being in 1997 for 1B and 2002 for TwinServer (although the last version of TwinServer has some limited support for 32-bit code, it can still run on a 286)
But, originally wasn't it mostly a network system to support network printers and file systems?
BTRIEVE would run on top of that. But, as I understand it, Netware wasn't required. They just went together really well.
Finally, especially with Netware 386, they supported "NLMs". "Netware Loadable Modules". This was what let you deploy applications to the network server. Some databases ported to that I believe. I think Informix had a NLM version of Informix OnLine.
So, to me, early Netware seemed more an interesting network utility more so than what I, at least, would consider an "OS". Perhaps it was an OS, but just sealed off. At least until NLMs arrived, making the system more extensible.
I have no idea what facilities were available to NLMs, or how they were developed.
I think they were usually developed in C. Metrowerks had a compiler that could build them, and Open Watcom can still do so as well.
My friends father worked for a shipping company and their office ran off a 286 Netware server until the early 2000's. It was a big white label tower with classic orange monochrome monitor and large Epson dot matrix printer with tractor feed paper.