For comparison, some thoughts about the opposite end of the spectrum for Pacific travel:
https://driftingclouds.net/2019/03/12/manufacturing-bula-mas...
It's a bit like going to Disneyland and complaining about the manufactured happiness there.
There are 300 other islands in Fiji off the extremely well-beaten path you walked where your experience could have been very different. Or you could have just visited a village that isn't part of any pre-packaged travel tour to find that in fact most rural Fijians will be extremely welcoming, hospitable, and amazing with kids without any expectation of payment.
Denarau is mostly multinational chain resorts (Accor, Sheraton, etc) so yes the experiences there are pretty boilerplate and "manufactured".
But there are numerous different resorts of all shapes and sizes in the Mamanuca and Yasawa Islands. There are resorts owned by foreigners like the one you went to, resorts owned by locals, resorts for backpackers, resorts run by their owners, and 5 star resorts. To assume you'll get the same there is like walking into McDonalds and saying that all restaurant food is crap.
I have a couple friends who have a knack of landing on their feet like that. Somehow, they can plan nothing and experience everything in great intimacy and depth. It's a skill. I have no doubt that if the technicians were not there at the same time, some other opportunity would have arisen.