Well we’re a bit unusual in that we both work in travel - and DH’s specialism is long haul luxury travel, so he did almost all of the planning himself using his connections.
We did break up the trip as well.
So we flew from London to LAX and had a couple of days in LA staying with friends - that’s about an 11h30 flight.
We then flew from LAX to Papeete in French Polynesia (Tahiti) with Air France I believe and that took about 8 hours.
From Papeete we then flew to Nadi, Fiji but I don’t think that’s a route that is still being flown unfortunately.
From Nadi we then flew on to Apia in Samoa.
We then went from Apia to New Zealand to visit family for a couple of months so not too helpful for getting back to the UK!
If we weren’t splitting our time as we were with some time in LA before and then New Zealand after, we would not have tried to do all 3 countries, but we wanted to make the most of the flying time and we both worked and still work remote jobs so could afford to have a big trip alongside work.
If I was going from the UK, I would probably look at going to either French Polynesia or Fiji & Samoa. French Polynesia with some time in LA on the way there and back would be a somewhat manageable trip I think.