The new nether generation is pretty consistently generating worlds where the Nether is mostly disconnected islands of netherrack over large voids and lava. There is no way to travel without bridging everywhere. Honestly, I think this is a misbalance of the difficulty, particularly for younger players.  The old generation (1.12.x and before) was much more playable; it was difficult and dangerous without being such a mess.  The new generation looks more like a mistake than on purpose.