I don't think its subjective to say that the NZ of today would ever oppose Nazi Germany.
I question the sustainability of NZ Five Eyes participation, its certainly at odds with NZs declared foreign policy and that of the opposition. I submit that over time NZ participation in Five Eyes will be abandoned, or rather less dramatically, the other nations will just come to other arraignments that mimic the five eyes agreement, but exclude NZ. How AUKUS came about could be the template for NZs defacto exclusion from Five Eyes, by Five Eyes becoming One Eye.
I don't agree with these negative viewpoints (which is fine, we all have a right to agree or disagree and amicably discuss etc), but you do raise some interesting points so lets discuss.
Firstly 5 Eyes - as NM has pointed out rather succinctly in a recent previous post where NZ fits in and there is no reason to suggest anything will change.
AUKUS is not the same as 5 Eyes etc.
As for WW2 comparisons, remember our defence (and FA) policies were aligned with London. Their naval (and air force etc) boards would determine what Cruisers we had and what aircraft the RNZAF would operate and they either provided them (at our cost) or denied them (like how the UK denied fighters and medium bombers for NZ initially as they were prioritised for Russia). Hence the turn to the USA for help.
Post war, even though the UK had devolved military planning to NZ (we became "independent" way back then), because of the UK's interest in SE Asia NZ still contributed to the UK's collective defence efforts (and were the primary reasons why, for example, NZ had an air combat force. Not so much for NZ's defence (which it ought to have been) but for political diplomacy reasons). (Interesting tidbit IIRC: RNZAF actually wanted the F-4 Phantom years before they were final options for replacements for the Canberra bomber in the mid/late 1960's. RNZAF initially wanted the UK production variant to be interoperable with the RAF Far East Air Force but once UK foreign policy changed and the UK signalled pulling out of SE Asia there went the RNZAF's plans to procure them ie govt didn't want to fund them because there was no joint political reasons to do so. RNZAF then tried to obtain the USAF F-4D variant later as the Canberra replacement and we know how that turned out)!
Anyway my long winded point is, when the UK pulled out of SE Asia (and prior, east of Suez when RNZAF leased RAF Vampire day-fighters and operated them in Cyprus, then later Venoms and Canberras in Singapore), one could say the NZDF lost a lot of its "grounding" (politically and militarily).
Then when the US kicked us out of ANZUS in 1985, again the NZDF lots a lot of its "grounding" (again both politically and militarily).
I would suggest the best way for NZ to regain "lethal" capabilities (across the spectrum) would be for the UK or US to somehow bring NZ back under its fold (and "ground" the ever-revolving door of NZ politicians tinkering with the NZDF trying to fit them into their worldviews).
There are endless possibilities here. One option could be greater RAF/RNZAF co-operation (like there was historically). Perhaps lease NZ some early model Typhoons (that are being withdrawn from RAF service) so RNZAF can learn to regain combat capabilities (similarly the USAF could do this with boneyard F16's or even Australia with surplus early model F/A-18's). Or perhaps the UK could stockpile some Seaceptor missiles here for their naval vessels for when they deploy into the Asia-Pacific area meaning they have the ability to re-load if required (after all any conflict in Asia will see traditional allied bases targeted, why not disperse some crucial assets to far-away places like NZ and OZ? Singapore bases some of its assets in NZ and elsewhere eg OZ, USA etc, for similar reasons). NZDF could contribute funding to the Seaceptor stocks and ensure NZ has quick access to more missiles etc.